Amino Acids[JOURNAL]
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200 papers
Evaluation of processing of canola protein isolate on postprandial plasma amino acid profiles in healthy, young females.
Boot N, Hermans WJH, Warnke I … +5 more , Overman A, van Kranenburg JMX, Senden JM, Verdijk LB, van Loon LJC
Amino Acids · 2025 Oct · PMID 41107640 · Full text
Canola protein is a rapeseed-derived protein that contains all essential amino acids in proportions that meet the WHO amino acid scoring requirements, making it an interesting protein for human food applications. It is c...
Canola protein is a rapeseed-derived protein that contains all essential amino acids in proportions that meet the WHO amino acid scoring requirements, making it an interesting protein for human food applications. It is currently unknown whether canola protein processing modulates postprandial plasma amino acid bioavailability in vivo in humans. This study compared postprandial plasma amino acid profiles following the ingestion of unprocessed (native) canola, processed canola, and whey protein isolate in healthy, young, females. In a randomized, clinical, cross-over design, 15 healthy young females (25 ± 3 y) participated in four test days on which they consumed 20 g protein as either native canola, enzyme processed or heat processed canola protein, or 20 g whey protein. Blood samples were collected for 5 h following protein ingestion to assess plasma amino acid concentrations. Ingestion of native canola protein resulted in lower increases in plasma total amino acid (TAA) concentrations compared to whey protein (3191 ± 794 vs. 4429 ± 84 µmol∙L, P < 0.001). Canola protein processing resulted in greater peak plasma total amino acids concentrations, reaching statistical significance for enzyme (3599 ± 687 µmol∙L, P = 0.045) but not heat (3565 ± 722 µmol∙L, P = 0.166) treated compared to native canola protein. Plasma total amino acid availability, expressed as incremental area under the curve over a 5 h postprandial period, did not differ between treatments and averaged 163 ± 81, 171 ± 76, 194 ± 82, and 207 ± 85 mmol∙300 min∙L following ingestion of native, enzyme- and heat processed canola, and whey protein, respectively (P > 0.05). Ingestion of whey protein allows for a more rapid postprandial rise in circulating essential and non-essential amino acids and greater postprandial plasma total amino acid availability when compared to the ingestion of native canola protein. Ingestion of enzyme- or heat processed canola protein accelerates the postprandial rise in circulating amino acids but does not further augment overall plasma amino acid availability throughout a 5 h postprandial period when compared to the ingestion of native canola protein.
Exploring claudin proteins: from sequence motifs to their impact on tight junction-mediated signaling pathways.
Bao L, Yang S, Zhao W … +1 more , Zuo Y
Amino Acids · 2025 Sep · PMID 40986072 · Full text
Claudin (CLDN) proteins are extensively studied due to their critical role in maintaining tissue barriers and cell polarity. However, significant gaps remain in understanding the functional mechanisms of their sequence m...
Claudin (CLDN) proteins are extensively studied due to their critical role in maintaining tissue barriers and cell polarity. However, significant gaps remain in understanding the functional mechanisms of their sequence motifs and the molecular mechanisms of their interactions with other tight junction proteins. This review systematically examines the multifunctional properties of the CLDN protein family from the perspectives of sequence and structure. During evolution, CLDN family members have developed highly conserved structural features, particularly key conserved sites within the first extracellular loop (ECL1) and the C-terminal PDZ-binding domain, which play a central role in regulating the barrier function of tight junctions, ion selectivity, and protein-protein interactions. Furthermore, the distribution pattern of acidic and basic amino acids in ECL1 has been shown to directly determine ion selectivity and paracellular permeability. Meanwhile, the assembly and functional stability of tight junctions are precisely regulated by the C-terminal PDZ-binding domain through its interactions with the ZO protein family. Additionally, the study further elucidates how CLDN proteins modulate critical signaling pathways governing cellular proliferation, survival, and permeability, thereby participating in diverse physiological and pathological processes. These insights have deepened the understanding of the functional diversity of CLDN proteins and provided a new theoretical basis for developing disease diagnostic markers and designing targeted treatment strategies based on CLDN proteins.
Protolytic properties and biological activity of spinorphin and its butyric acid derivatives in aqueous solution.
Pająk M, Kamysz E, Banach M … +4 more , Jankowski WM, Tarasiuk-Zawadzka A, Fichna J, Woźniczka M
Amino Acids · 2025 Sep · PMID 40965709 · Full text
The present work describes the protolytic properties and in vitro biological activity of spinorphin (Leu-Val-Val-Tyr-Pro-Trp-Thr) and three spinorphin derivatives containing butyric acid residue: Butyryl-Lys-Lys-Leu-Leu-...
The present work describes the protolytic properties and in vitro biological activity of spinorphin (Leu-Val-Val-Tyr-Pro-Trp-Thr) and three spinorphin derivatives containing butyric acid residue: Butyryl-Lys-Lys-Leu-Leu-Val-Tyr-Pro-Trp-Thr, Butyryl-Lys-Lys-Leu-Val-Val-Tyr-Pro-Trp-Thr (butyric acid bound to the α-amino group of lysine), Lys(Butyryl)-Lys-Leu-Val-Val-Tyr-Pro-Trp-Thr (butyric acid bound to the ε-amino group of lysine) in an aqueous solution. The overall protonation constants and the stepwise dissociation constants of the ligands studied were calculated by the potentiometric method. The percentage of each species formed was estimated from the species distribution curves as a function of pH. The biological activity of all tested compounds was characterized in vitro, in the neutral red uptake and Griess assay tests in RAW264.7 macrophage cell line. The three protonation constants for spinorphin and four for its derivatives suggest that metal ions may bind to these peptides and form complexes by coordination with the functional groups of the respective amino acid residues. In vitro biological activity tests suggest that two peptides deserve attention for their potential anti-inflammatory role.
Associations between XRCC1-Arg399Gln polymorphism and the risk of prostate cancer: an updated meta-analysis.
Deng J, Xu L, Zhou J … +1 more , Huang H
Amino Acids · 2025 Sep · PMID 40963005 · Full text
The X-ray repair cross-complementary group 1 (XRCC1) gene 399 codon polymorphism may alter the structure of DNA repair enzymes to regulate DNA repair capacity. Impaired DNA repair ability can lead to the development of c...
The X-ray repair cross-complementary group 1 (XRCC1) gene 399 codon polymorphism may alter the structure of DNA repair enzymes to regulate DNA repair capacity. Impaired DNA repair ability can lead to the development of cancers such as prostate cancer (PCa). Although the association between the XRCC1 codon 399 polymorphism and the risk of PCa has been widely reported, the results have not been clear. Data were collected from PubMed, EMBASE, the Wanfang Database, CNKI and the Web of Science. A total of 20 case‒control studies were selected for inclusion in this updated analysis to determine the association between the XRCC1 codon 399 polymorphism and the risk of PCa. The crude odds ratio (OR) and 95% confidence interval (CI) were calculated using Stata (version 18) software to evaluate the association between the XRCC1-Arg399Gln polymorphism and prostate cancer. We identified 20 eligible reports that included 5803 cases of prostate cancer and 5470 controls. Our meta-analysis revealed a significant association between the XRCC1-Arg399Gln polymorphism and the risk of prostate cancer. In particular, according to the recessive models, this polymorphism was associated with a significantly increased prevalence of prostate cancer in Asian populations (AA versus AG + GG: OR = 1.255, 95% CI = 1.063-1.481, P = 0.507, I, < 25%). Based on these results, the XRCC1-Arg399Gln polymorphism may be a risk factor for prostate cancer and can be used as a biomarker to predict the prognosis of prostate cancer.
Rational designing and synthesizing an antimicrobial peptide from bovine milk casein and evaluating its biological properties.
Pourhosseini SR, Akbari B, Ghods E … +2 more , Veisi K, Madanchi H
Amino Acids · 2025 Sep · PMID 40956460 · Full text
The overuse of antibiotics has led to a growing crisis-antimicrobial resistance, making it harder to treat infections and pushing scientists to find new solutions. Among the most promising alternatives are bioactive pept...
The overuse of antibiotics has led to a growing crisis-antimicrobial resistance, making it harder to treat infections and pushing scientists to find new solutions. Among the most promising alternatives are bioactive peptides, especially antimicrobial peptides, which offer broad-spectrum activity with a lower risk of resistance. One exciting source of these peptides is milk, particularly casein-derived peptides, which naturally possess antimicrobial properties. This study focused on bovine milk casein to design and synthesize a novel antimicrobial peptide. We evaluated several properties, such as antimicrobial activity, cytotoxicity, stability, and structure, using computational predictions to select the most promising candidate. The peptide NCP1 emerged as the best option and was synthesized for lab testing. Our results showed that NCP1 has antifungal activity and effectively stops the growth of Candida albicans with a minimum fungicidal concentration (MFC) of 250 µg/mL in less than four hours. It also prevented biofilm formation, interacted with DNA, and bound to ergosterol, ultimately damaging the fungal cell wall. Additionally, NCP1 demonstrated feeble antibacterial effects, particularly against Staphylococcus aureus and Pseudomonas aeruginosa. However, its antibacterial impact weakened over time due to interactions with environmental salts. Since the NCP1 peptide has low cytotoxicity and kills the yeasts selectively, further refinements to improve its potency and stability could pave the way for our future study of the presentation of a potent antimicrobial peptide.
Metabolic alterations in diabetic patients: aqueous humor profiling for biomarker discovery.
Zemitis A, Svjascenkova L, Bleidele S … +4 more , Veitners A, Vanags J, Klavins K, Laganovska G
Amino Acids · 2025 Sep · PMID 40944756 · Full text
Diabetic retinopathy, a leading cause of vision loss in working-age populations, is a severe complication of diabetes mellitus. Metabolomics, a key approach in systems biology, offers insights into the complex pathophysi...
Diabetic retinopathy, a leading cause of vision loss in working-age populations, is a severe complication of diabetes mellitus. Metabolomics, a key approach in systems biology, offers insights into the complex pathophysiology of diabetes by analyzing low-molecular-weight compounds in biological contexts. This study investigated metabolite alterations in the aqueous humor of diabetic and non-diabetic patients undergoing cataract surgery to identify potential biomarkers associated with diabetes. Aqueous humor samples from 191 patients (48 diabetic, 143 non-diabetic) were analyzed using targeted liquid chromatography-mass spectrometry. Metabolite data were normalized and statistically evaluated using univariate analysis, including fold change calculations, t-tests, and volcano plots. Pathway enrichment analysis was performed using KEGG, SMPDB, and RaMP-DP databases. Key findings revealed differential abundance of several metabolites, including upregulated 3-hydroxykynurenine, histamine, and octanoylcarnitine, and downregulated putrescine in diabetic patients. Although some metabolites exhibited low p-values (< 0.05), high FDR limited the statistical robustness of these findings. Quantitative enrichment analysis suggested potential involvement of the kynurenine pathway and tryptophan catabolism in diabetes-related metabolic changes. The study highlights the potential roles of these metabolites in diabetes-related ocular changes, supported by prior research linking them to oxidative stress, inflammation, and metabolic dysregulation. Antioxidative therapies targeting diabetes-associated metabolic alterations may offer potential for mitigating diabetes-related complications. High FDR underscores the need for cautious interpretation and further validation in larger cohorts. Future studies should focus on longitudinal analyses and mechanistic investigations to clarify the diagnostic and prognostic potential of these metabolites in diabetic retinopathy and other diabetes-related complications.
Exploring the therapeutic potential of L-arginine in chronic anal fissure management: a comprehensive review.
Motamed-Gorji N, Masoodi M, Sikaroudi MK … +2 more , Agah S, Masoodi N
Amino Acids · 2025 Sep · PMID 40924217 · Full text
Anal fissure causes pain and bleeding during or after bowel movements, significantly impacting individuals' quality of life. Current treatments aim to interrupt this cycle but have associated risks and limitations. The e...
Anal fissure causes pain and bleeding during or after bowel movements, significantly impacting individuals' quality of life. Current treatments aim to interrupt this cycle but have associated risks and limitations. The emergence of arginine, crucial for protein creation and nitric oxide (NO) production, presents an intriguing therapeutic avenue by the impact on reducing anal sphincter pressure and enhancing anoderm blood flow, due to its roles in vasodilation, anti-inflammatory responses, and collagen synthesis, which can promote wound healing and highlighting its potential as an alternative therapy. However, the effectiveness of oral supplementation remains debated, indicating the need for further elucidation of its mechanisms. Its multifaceted mechanisms can present an exciting avenue for nuanced treatments, urging further exploration to refine its role in chronic anal fissure management. This review comprehensively explores the therapeutic landscape of L-arginine in chronic anal fissure management, integrating recent research studies and clinical investigations.
IGF2BP1-mediated methylation of ABCA1 facilitates tumor progression by affecting cholesterol metabolism in lung adenocarcinoma.
Xu S, Liu K, Chen Z … +2 more , Tang W, Chen Z
Amino Acids · 2025 Aug · PMID 40844715 · Full text
ABCA1 is a key protein in maintaining cholesterol homeostasis, and its abnormal expression is associated with the progression of many cancers. Nonetheless, the specific molecular mechanisms by which ABCA1 facilitates the...
ABCA1 is a key protein in maintaining cholesterol homeostasis, and its abnormal expression is associated with the progression of many cancers. Nonetheless, the specific molecular mechanisms by which ABCA1 facilitates the development of LUAD remain largely unexplored, necessitating further in-depth investigation. The TCGA-LUAD database was used to analyze the expression of ABCA1 in LUAD tissues. Subsequently, a cell model with overexpressed ABCA1 was constructed for verification through cell experiments. Cell function was evaluated using the Transwell assay and the colony formation assay. Intracellular cholesterol levels were detected using a kit. At the same time, the online database RM2 Target was employed to predict upstream factors that may have a methylation regulatory relationship with ABCA1. On this basis, Dot blot and MeRIP-qPCR techniques were employed to determine the degree of m6A modification. To clarify the mechanism of IGF2BP1 regulating ABCA1 through the m6A pathway, RNA pull-down binding experiments were carried out, and changes in mRNA stability were assessed using actinomycin D treatment. Finally, the biological function of the IGF2BP1/ABCA1 signaling axis during the growth and metastasis of LUAD in vivo was evaluated by establishing a xenograft animal model. Bioinformatics analysis and cell experimental results confirmed the low expression of ABCA1 in LUAD tissues and cells. ABCA1 significantly inhibited cell proliferation, migration, and invasion capabilities, promoted apoptosis, and reduced intracellular cholesterol levels. From a molecular perspective, IGF2BP1 recognized and bound to methylation sites on ABCA1 mRNA, thereby accelerating its degradation process, resulting in a substantial decrease in the stability of ABCA1 mRNA. Moreover, in vivo and in vitro experiments further confirmed that IGF2BP1 affected cholesterol metabolism by regulating the expression of ABCA1, thereby facilitating the malignant progression of LUAD. Overall, our research revealed that IGF2BP1 affects cholesterol metabolism by reducing the stability of ABCA1 mRNA through m6A modification, thereby boosting the malignant progression of LUAD and formulating a theoretical basis for subsequent LUAD treatment.
Insight into the structure of antitubercular Callyaerins: conformational studies and synthesis of a unique dehydroamino acid, β-aminodehydroalanine.
Banaś K, Lenartowicz P, Siodłak D
Amino Acids · 2025 Aug · PMID 40826284 · Full text
β-Aminodehydroalanine, ΔAla(β-NH), (2,3-diaminoprop-2-enoic acid), is a unique dehydroamino acid and a central component of Callyaerins A-M and Callynormine A. The presence of this unusual structural element containing a...
β-Aminodehydroalanine, ΔAla(β-NH), (2,3-diaminoprop-2-enoic acid), is a unique dehydroamino acid and a central component of Callyaerins A-M and Callynormine A. The presence of this unusual structural element containing an enamine functional group may be related to the antitubercular activity of Callyaerins. According to The WHO Global Tuberculosis Report tuberculosis is the second leading cause of death worldwide caused by a single infectious agent. Therefore, it is essential to understand the molecular structure of these peptides in more detail. To investigate the conformational properties of the ΔAla(β-NH) residue, a series of model compounds: Ac-(Z/E)-ΔAla(β-NHMe)-NHMe, Ac-(Z/E)-ΔAla(β-NHMe)-NMe, Boc-Gly-(Z)-ΔAla(β-NHMe)-OMe, and Boc-Gly-(Z)-ΔAla(β-Leu-OMe)-OMe, were selected for quantum chemical calculations and/or synthesized. Two conformations, β2 (φ,ψ ~ - 120°, 20°) and α (φ,ψ ~ - 70°, - 15°) are predicted as the most preferable, regardless of the geometry of isomer (Z/E), polarity of environment, and order (2°/3°) of C-terminal amide group. The N-H⋯O hydrogen bond involving the N-H group in the β position of the side chain as a donor is a significant stabilizing factor. The Z isomer is predicted to be the most stable and has been synthesized. The following synthesis method is proposed: Ser → ΔAla → ΔAla(β-Br) → ΔAla(β-NH). The advantages of the proposed method are: (i) serine as the starting substrate, (ii) mild alkaline conditions, (iii) avoidance of the reactive intermediate α-formylglycine.
Post-translational modifications of ezrin: a crucial regulator for diseases.
Li YC, Yuan HK, Yin LM
Amino Acids · 2025 Aug · PMID 40782214 · Full text
Ezrin is a crucial structural protein that connects the plasma membrane to the actin cytoskeleton to maintain cell shape, adhesion, and motility. Post-translational modifications (PTMs) play a key role in the regulation...
Ezrin is a crucial structural protein that connects the plasma membrane to the actin cytoskeleton to maintain cell shape, adhesion, and motility. Post-translational modifications (PTMs) play a key role in the regulation of various biological functions and have been implicated in a range of pathological conditions. With the help of PTMs, ezrin not only plays a structural role in connecting the cell membrane to F-actin, but also participates in transmitting cellular signals including those related to inflammatory responses. In this study, we reviewed the key sites and domains involved in the different PTMs of ezrin, including acetylation, lactylation and phosphorylation. We analyzed the regulation of biological processes mediated by different PTMs of ezrin, such as cell migration, inflammation regulation and cell stiffness. In addition, we examined the mutual regulatory effects of different modifications of ezrin, including regulation of ezrin phosphorylation by kinases and phosphatases, and so on. Increasing evidence suggests that PTMs of ezrin are involved in cancer, respiratory diseases and urological diseases. These studies provide novel insights into the design of new disease treatment strategies targeting ezrin.
The effect of L-Arg supplementation on L-Arg/NO metabolic and AMPK/ACC-1 signalling pathways in adipose cells (3T3 L1).
Prashath S
Amino Acids · 2025 Aug · PMID 40764680 · Full text
L-arginine (L-Arg) is metabolised in the cell to generate nitric oxide (NO) and citrulline via nitric oxide synthase (NOS). NO is an important cellular signalling molecule that regulates lipid and glucose metabolism. The...
L-arginine (L-Arg) is metabolised in the cell to generate nitric oxide (NO) and citrulline via nitric oxide synthase (NOS). NO is an important cellular signalling molecule that regulates lipid and glucose metabolism. The biological availability of NO is affected by the NOS inhibitor; N-nitro-L-Arg methyl ester (L-NAME) and the external NO donor; S-nitroso-N-acetyl-D, L-penicillamine (SNAP). Mouse adipocyte 3T3 L1 cells were cultured with 0, 400 and 800 µM L-Arg or control complete DMEM media. The impact of L-NAME (4 mM), and SNAP (100 µM) was also analysed. The cell fitness was similar and the mRNA levels of AMPK was increased and ACC-1 was decreased, whilst the activation of AMPK and ACC-1 was decreased upon the addition of exogenous L-Arg. Transcript and protein levels of AMPK and ACC-1 were regulated by addition of L-NAME and SNAP, however the impact of these targets was related to the concentration of L-Arg added to the cells and the culture time point of analysis. NO in the form of NO in cell culture supernatant was elevated in 400 and 800 µM L-Arg cultures. L-NAME significantly inhibited NO production from adipose cells in a time-dependent manner and subsequently impacted AMPK and ACC expression. Associated with these changes were changed in the concentration of L-Arg, L-Cit and L-Orn in the culture media. Collectively, these results show that excess L-Arg is sensed by the cell which then regulates AMPK and ACC-1 expression in response. The findings could have implications in modulation of signalling pathways for treating obesity and obesity induced diabetic mellitus.
Protective effects of S-adenosyl methionine on oxidative stress and tissue damage in STZ-induced diabetic rats.
RahimBakhsh A, Kheirollahi A, Vatannejad A … +2 more , Shokrpoor S, Mohammadi R
Amino Acids · 2025 Jul · PMID 40742482 · Full text
BACKGROUND: Oxidative stress is a key contributor to the progression of diabetes mellitus and its associated complications. Recently, S-adenosyl methionine (SAM) has shown promise in mitigating oxidative stress and impro...
BACKGROUND: Oxidative stress is a key contributor to the progression of diabetes mellitus and its associated complications. Recently, S-adenosyl methionine (SAM) has shown promise in mitigating oxidative stress and improving glucose metabolism. This study aimed to investigate the effects of SAM supplementation on biochemical parameters, oxidative stress markers, and histopathological alterations in the kidneys and liver of streptozotocin (STZ)-induced diabetic rats. METHODS: Eighteen male Wistar rats were randomly divided into three groups (n = 6 per group): non-diabetic control, diabetic control, and diabetic rats treated with SAM (10 mg/kg/day, intraperitoneally) for 4 weeks. Fasting blood glucose, renal and hepatic biochemical markers (urea, creatinine, ALT, AST), and oxidative stress markers (malondialdehyde, protein carbonyls, total antioxidant capacity) were measured. Histopathological changes in kidney and liver tissues were also assessed. RESULTS: Diabetic rats treated with SAM exhibited minor, non-significant changes in fasting blood glucose, urea, creatinine, ALT, and AST levels. In contrast, treatment with SAM in diabetic rats significantly reduced malondialdehyde and protein carbonyl levels in both kidney and liver tissues compared to the diabetic control group (P < 0.05). Furthermore, histopathological analysis revealed improved tissue architecture and reduced pathological changes in the diabetic group treated with SAM. CONCLUSION: Our findings demonstrated that SAM supplementation exerts significant antioxidant and histopathological protective effects against diabetes-induced damage in kidney and liver tissues.
CacyBP/SIP - RPL6 interaction: potential influence on ribosome function.
Jurewicz E, Maksymowicz-Trivedi M, Saberi-Khomami O … +8 more , Iwańska O, Starosta A, Kilańczyk E, Bieganowski P, Jarmuła A, Leśniak W, Filipek S, Filipek A
Amino Acids · 2025 Jul · PMID 40691326 · Full text
Previously, we have shown that CacyBP/SIP interacts with NPM1, a protein involved in ribosome biogenesis. In this work, we extended our previous studies to look for the potential impact of CacyBP/SIP on ribosome biogenes...
Previously, we have shown that CacyBP/SIP interacts with NPM1, a protein involved in ribosome biogenesis. In this work, we extended our previous studies to look for the potential impact of CacyBP/SIP on ribosome biogenesis and/or function. Using mass spectrometry analysis, we have found that several RPs could be potential CacyBP/SIP targets. Since RPL6 was one of the proteins with the best quality scores identified in this analysis we focused on the possible interaction between CacyBP/SIP and RPL6. By applying various biochemical methods, we confirmed this interaction and showed that it was direct. Moreover, in silico analysis allowed us to establish the domains/fragments of both proteins involved in the binding. To further explore the possible role of CacyBP/SIP in ribosome function we performed several analyses using neuroblastoma NB2a cell line with stably silenced CacyBP/SIP expression. We have found, by applying OPP (O-propargyl-puromycin), which labels nascent polypeptides, that the number of cells with enhanced staining in the perinuclear area, reminiscent of rough ER localization, was significantly lower in the cell line with diminished CacyBP/SIP level. To verify the influence of CacyBP/SIP on the efficiency of protein synthesis we investigated the level of Hsp70, a stress-inducible protein, in NB2a cells subjected to heat shock. The results, showing markedly higher Hsp70 production in control cells, indicate that CacyBP/SIP, most probably through interaction with RPL6 and/or other RPs, may have some influence on ribosome function and, possibly, on protein synthesis in the cell.
Construction of a co-reaction system for ethanol-promoted gamma-aminobutyric acid synthesis by Pediococcus pentosaceus.
Yang SY, Li YJ, Hong WC
Amino Acids · 2025 Jul · PMID 40668313 · Full text
The biotransformation of L-glutamic acid (L-Glu) to γ-aminobutyric acid (GABA) using glutamate decarboxylase (GAD) in microbial whole cells represents an ideal approach for biosynthesis of food-grade and pharmaceutical-g...
The biotransformation of L-glutamic acid (L-Glu) to γ-aminobutyric acid (GABA) using glutamate decarboxylase (GAD) in microbial whole cells represents an ideal approach for biosynthesis of food-grade and pharmaceutical-grade GABA. To overcome the cell membrane barrier, enhance mass transfer efficiency in the whole-cell reaction system, and improve GABA biosynthesis efficiency, we established a novel ethanol-enhanced whole-cell biocatalytic co-reaction system through systematic investigations on the enzymatic characteristics of GAD in Pediococcus pentosaceus whole cells and the regulatory effects mediated by ethanol. The results showed that the optimal reaction pH and temperature for GAD in P. pentosaceus whole cells were 4.2 and 32 °C, respectively. A 7.5% (v/v) ethanol concentration significantly promoted the activity of whole-cell GAD, but reduced its stability. Through orthogonal test optimization, the optimal reaction conditions for ethanol-promoted GABA synthesis via P. pentosaceus whole-cell transformation were as follows: mixing 0.3 M monosodium glutamate (MSG) solution with 100 mg/ml cell suspension at a 1:1 volume ratio, adding 40 g/l of L-Glu/MSG (2:1) solid mixture, adjusting the final ethanol concentration to 3.75% (v/v), reacting at pH 4.2, 28 °C for 40 h. Under these conditions, the GABA yield reached 366.07 ± 5.57 mM, which was 21.44 ± 1.85% higher than that of the control group without ethanol. As an enhancer, ethanol demonstrates great application potential in GABA production via whole-cell transformation due to its high safety and ease of use.
Proteins and peptides as antigen candidates for the immunodiagnosis of hepatitis D.
Xavier SR, Dos Santos Barcelos IC, Gandra IB … +22 more , Pereira SP, Ribeiro AJ, Silva KA, Resende CAA, da Silva Lopes L, Machado RCR, Silva LMS, Silva LS, Ferreira LC, de Souza LFA, Souza RB, Passos-Silva AM, da Paz MC, Fumagalli MAC, Coelho EAF, Giunchetti RC, Machado JM, Gonçalves AAM, Dos Santos Pereira S, da Matta DA, Souza Vieira D, Galdino AS
Amino Acids · 2025 Jul · PMID 40613912 · Full text
Designing innovative, accurate, universal, and accessible diagnostic tests is mandatory to improve screening, prevention, and management of hepatitis D (HD), especially in endemic areas with poor infrastructure and restr...
Designing innovative, accurate, universal, and accessible diagnostic tests is mandatory to improve screening, prevention, and management of hepatitis D (HD), especially in endemic areas with poor infrastructure and restricted access to public health care. Recombinant proteins (RP), recombinant multiepitope proteins (RMP), and synthetic peptides have been extensively reported as tools for efficient immunodiagnosis of several diseases. This review aimed to discuss the use of these antigens for the immunodiagnosis of HD. To this end, a bibliographic study was conducted in the PubMed database by searching the primary ("Hepatitis D" and "Hepatitis Delta"), secondary ("Detection", "Diagno*", "Diagnosis", "Immunodiagnosis", and "Serodiagnosis"), and tertiary ("Chimera", "Epitope", "Peptide"; "Protein" and "Recombinant") descriptors, including papers published up to January 2025. Review articles and case reports were excluded. Only nine articles (five for RP, three for synthetic peptides, and one for RMP) met the inclusion criteria, revealing that there are very few studies on this subject, particularly when compared to the advances made in the diagnosis of hepatitis A, B, and C. Despite the scarcity of articles published in the literature, six of the nine analyzed studies corroborate the potential of these antigens to effectively replace traditional diagnostic methods, including development of rapid tests. These data highlight the need for further studies to assess the potential of RP, RMP, and synthetic peptides for immunodiagnosis of HD, aiming to increase the accuracy of diagnosis, as well as improve monitoring and prevention.
Transport of the uremic toxin symmetric dimethylarginine (SDMA) by renal transport proteins.
Scherpinski LA, Fromm MF, Maas R … +1 more , König J
Amino Acids · 2025 Jun · PMID 40555835 · Full text
The L-arginine derivative and uremic toxin symmetric dimethylarginine (SDMA) is an independent risk marker for total mortality and cardiovascular events. Interferences with L-arginine- or L-homoarginine-related signaling...
The L-arginine derivative and uremic toxin symmetric dimethylarginine (SDMA) is an independent risk marker for total mortality and cardiovascular events. Interferences with L-arginine- or L-homoarginine-related signaling, metabolism, or transport have been proposed as underlying mechanisms. SDMA is endogenously formed and predominantly eliminated via the kidney. Whereas for L-arginine and other L-arginine derivatives such as L-homoarginine and asymmetric dimethylarginine (ADMA) key transport proteins involved in the cellular uptake and release have been characterized, comparable data for the transport of SDMA are lacking.Using HEK cell lines overexpressing the transport proteins OCT2, OATP4C1, MATE1, OAT4, and OAT10, which are all expressed in renal proximal tubule cells, and the ubiquitously-expressed transport protein CAT1 we performed uptake experiments demonstrating that SDMA is a substrate for CAT1, OATP4C1, OCT2, and MATE1 in physiological concentrations, but not of OAT4 and OAT10. K values for OATP4C1-, CAT1-, and MATE1-mediated SDMA uptake were 70 µM, 246 µM, and 1 973 µM, respectively. For OCT2-mediated uptake, no saturation could be reached, precluding the determination of a K value. Uptake of SDMA by these transporters could be inhibited by known substrates of the respective transport proteins. Furthermore, CAT1 and OATP4C1 also mediate the efflux of SDMA out of cells.These results show that SDMA is a substrate of renally-expressed transport proteins OATP4C1, OCT2, and MATE1 and of CAT1 demonstrating that these transporters are involved in the homeostasis of this uremic toxin and possible sites of interactions with related compounds.
Enhanced γ-aminobutyric acid levels promote degeneration of silk glands following spermidine supplementation in Bombyx mori.
Didugu BGL, Mamillapalli A
Amino Acids · 2025 Jun · PMID 40514595 · Full text
Silk glands are modified labial glands that produce silk which has immense commercial importance. Silk is extruded out in liquid form after which the glands undergo autophagy and apoptosis during larval to pupal transiti...
Silk glands are modified labial glands that produce silk which has immense commercial importance. Silk is extruded out in liquid form after which the glands undergo autophagy and apoptosis during larval to pupal transition. Biogenic amines, specially spermidine and γ-aminobutyric acid (GABA) are known to play an important role in autophagy. Yet, GABA is not identified in the silk glands till now and therefore its role in autophagy remains unknown. Current study aimed to evaluate role of biogenic amines in the autophagy of silk glands. Fifth instar silkworms were fed with control and spermidine supplemented mulberry leaves under controlled conditions. Qualitative and quantitative analysis of biogenic amines were analyzed in silk glands of control and spermidine fed groups at the end of feeding stage, spinning and pre-pupal stages. Biogenic amines were significantly decreased in the silk glands from feeding stage to non-feeding prepupal stages. Elevated levels of biogenic amines; putrescine, spermidine, and spermine were observed in silk glands at pre-pupal stage in the spermidine fed group. The unknown biogenic amine whose levels were significantly elevated during silk gland degeneration in both control and spermidine fed groups was identified as GABA by spectroscopic techniques. This is the first report of the identification of GABA in the silk glands of Bombyx mori which increased significantly following spermidine supplementation, resulting in elevated levels of calcium deposits, contributing to the early degeneration of the silk glands.
Identification of potential inhibitors of interleukin-2-inducible T-cell kinase: insights from docking, molecular dynamics, MMPBSA and free energy landscape studies.
Ahmed S, Choudhury A, Saeed MU … +6 more , Mohammad T, Hussain A, Alajmi MF, Yadav DK, Shamsi A, Hassan MI
Amino Acids · 2025 Jun · PMID 40464789 · Full text
Interleukin-2-inducible T-cell kinase (ITK) is an essential enzyme that plays a key role in both the activation and differentiation of T-cells. As a member of the Tec family of non-receptor tyrosine kinases, ITK is predo...
Interleukin-2-inducible T-cell kinase (ITK) is an essential enzyme that plays a key role in both the activation and differentiation of T-cells. As a member of the Tec family of non-receptor tyrosine kinases, ITK is predominantly expressed in T cells, exerting a critical influence on T-cell receptor signaling and downstream pathways. Moreover, ITK regulates cytokine production, notably interleukin-2 (IL-2), and the differentiation of Th2 cells. In the context of immunology, ITK has garnered significant attention, particularly for its potential to address immune-related conditions such as cancer and autoimmune diseases, including lymphoproliferative diseases. In this study, we performed a structure-based virtual screening utilizing a library of plant-based small molecules to identify inhibitors of ITK. The initial selection of phytochemicals was guided by adherence to the Lipinski rule of five. After molecular docking, top-ranked hits in terms of binding affinity underwent screening for physicochemical and pharmacokinetic properties and PASS analyses. The three selected phytochemicals, Withanolide A, Amorphispironon E, and 27-Deoxy-14-hydroxywithaferin A (27-DHA) demonstrated remarkable binding affinity to ITK with a docking score of - 9.2, - 9.1, and - 9.1 kcal/mol, respectively. All the phytochemicals showed specific binding to the ATP-binding site of ITK as revealed by protein structure network analysis. These selected phytoconstituents underwent all-atom molecular dynamics (MD) simulations, spanning 100 ns each. The simulation results showed that ITK with elucidated compounds exhibited stability with minimal dynamics. In addition, we performed an MM-PBSA analysis, which indicated a strong binding affinity. This study highlights the potential of Withanolide A, Amorphispironon E, and 27-DHA as preliminary leads for further experimental validation and preclinical investigation toward therapeutic development.
Synthesis of novel bisazlactones and their applications in the synthesis of a new family of pseudo-peptide enamides with anti-cancer properties.
Halimehjani AZ, Noorakhtar F
Amino Acids · 2025 May · PMID 40423882 · Full text
Pseudo-peptides are an important category of biologically active artificial small molecules. To access these important molecules, a novel series of bisazlactones was synthesized via the Erlenmeyer-Plöchl reaction, using...
Pseudo-peptides are an important category of biologically active artificial small molecules. To access these important molecules, a novel series of bisazlactones was synthesized via the Erlenmeyer-Plöchl reaction, using glycine- and terephthaloyl-based diacid with aldehydes. These bisazlactones were then utilized as efficient intermediates in reactions with primary and secondary amines, providing novel pseudo-peptides containing enamide groups in high to excellent yields. The selected pseudo-peptide enamides exhibited selective cytotoxicity against hepatocarcinoma cells, while exhibiting negligible impact on normal mammalian cells. Notably, compound 6y displayed superior anti-cancer activity compared to the others.
Evaluation of safe utilization of L-threonine for supplementation in healthy adults: a randomized double blind controlled trial.
Matsumoto H, Miura N, Naito M … +1 more , Elango R
Amino Acids · 2025 May · PMID 40419835 · Full text
L-threonine is used in dietary supplements and nutritional products ingested by healthy consumers. The objective of this study was to determine in a randomized double blind controlled clinical trial the safety and tolera...
L-threonine is used in dietary supplements and nutritional products ingested by healthy consumers. The objective of this study was to determine in a randomized double blind controlled clinical trial the safety and tolerability of L-threonine used as graded doses in supplements for 4 weeks. Healthy male adults (age 42.9) ingested randomly placebo or different doses of L-threonine (0, 3, 6, 9, 12 g/day) for 4 weeks using a crossover design. At the end of supplementation period, the subjects visited the clinic for medical examination, anthropometric parameter measurements, blood sampling for biochemical tests including amino acid concentrations in plasma, measurement of blood pressure and heart rate, and dietary intake evaluation. Adverse events were recorded all along the trial. None of the anthropometric parameters measured, dietary intake and the biochemical parameters were affected by L-threonine supplementation except a non-specific minor increase in plasma aspartate amino transferase and creatine kinase which was measured in the group supplemented with 9 g L-threonine per day but not with the 12 g per day dose. Also, the concentration of L-threonine as well as the concentration of its metabolite L-2-amino butylate were found to be increased in plasma after supplementation with 6, 9, 12 g/day L-threonine. The moderate and mild adverse events were found to occur at random. All symptoms disappeared during the supplementation period despite continuous L-threonine supplementation. These results of this study indicate a no-observed-adverse-effect-level (NOAEL) value for L-threonine to be 12 g/day in healthy adult males. This study was registered at jRCT as jRCT1050230137.
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