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Investigation of the links between heterocyst and biohydrogen production by diazotrophic cyanobacterium A. variabilis ATCC 29413

Salleh SF, Kamaruddin A, Uzir MH, Karim KA, Mohamed AR

Arch Microbiol, 2016 Mar;198(2):101-13.
PMID: 26521065 DOI: 10.1007/s00203-015-1164-6

This work investigates the effect of heterocyst toward biohydrogen production by A. variabilis. The heterocyst frequency was artificially promoted by adding an amino acid analog, in this case DL-7-azatryptophan into the growth medium. The frequency of heterocyst differentiation was found to be proportional to the concentration of azatryptophan (0-25 µM) in the medium. Conversely, the growth and nitrogenase activity were gradually suppressed. In addition, there was also a distinct shortening of the cells filaments and detachment of heterocyst from the vegetative cells. Analysis on the hydrogen production performance revealed that both the frequency and distribution of heterocyst in the filaments affected the rate of hydrogen production. The highest hydrogen production rate and yield (41 µmol H2 mg chl a(-1) h(-1) and 97 mL H2 mg chl a(-1), respectively) were achieved by cells previously grown in 15 µM of azatryptophan with 14.5 % of heterocyst frequency. The existence of more isolated heterocyst has been shown to cause a relative loss in nitrogenase activity thus lowering the hydrogen production rate.

Matched MeSH terms: Amino Acids, Diamino
Fulltext Invadopodia formation is a critical step in cancer cell invasion: the effect of passage number on invadopodia formation in MDA-MB-231 breast cancer cell line

Hamad Ali Hamad, Cheah, Yoke Kqueen, Nur Fariesha MD Hashim

Life Sciences, Medicine and Biomedicine, 2018;2(2):1-5.
MyJurnal

High invasive cancer cells are thought to recruit specialised actin-rich protrusions for invasion in metastasis process. These protrusions are termed invadopodia. To study invadopodia formation, one of the first challenges faced by researchers has been to optimise the cell line passage number in order to be used for the invadopodia assay. Therefore, this study aims to investigate the effects of the passage number on invadopodia formation in MDA-MB-231 breast cancer cell line. Invadopodia assay was used to achieve the aim of the study. The results provided evidence that invadopodia formation is affected by the high passage number. The cells were also tested with dimethyloxalylglycine (DMOG) a hypoxic mimicking agent which is known to be an invadopodia inducer, the results showed that the cells in low passage number (P7) treated with DMOG increase the cells forming invadopodia, while the cells with high passage number (P35) showed that DMOG fails to stimulate the cells to form invadopodia. Furthermore, the cells with high passage number after passage 15 are starting to lose the ability to degrade the gelatin. In conclusion, this study suggests that only cells with a low passage number, less than passage 15 should be used in the study of invadopodia formation to obtain the results in the search for molecular targets and signaling at invadopodia.

Matched MeSH terms: Amino Acids, Dicarboxylic
Extraction and characterization of gelatin from different marine fish species in Malaysia

Irwandi, J., Faridayanti, S., Mohamed, E.S.M., Hamzah, M.S., Torla, H.H., Che Man, Y.B.

International Food Research Journal, 2009;16(3):381-389.
MyJurnal

Gelatins from the skin of four local marine fish, namely “kerapu” (Epinephelus sexfasciatus), “jenahak” (Lutjianus argentimaculatus), “kembung” (Rastrelliger kanagurta), and “kerisi” (Pristipomodes typus) have been successfully extracted by acid extraction. Results characterization showed that the fish gelatins were comparable to the fish gelatins from other fish species previously reported. They appeared snowy white in color with crystal-like and light texture. The gelatine extracted from “kerapu” had the strongest fishy odor, followed by the gelatines derived from “jenahak”, “kembung” and “kerisi”. In terms of bloom strength, the gelatin extracted from “kerapu” was found to be the strongest one compared to others, with the bloom value of more than 2000 g. The gelatins developed in this study contained almost all essential amino acids, with glycine being the most predominant one.

Matched MeSH terms: Amino Acids, Essential
Fulltext Computational studies on the process of peptide bond formation

Monajemia, H., Daud, M.N., Zain, S.M., Wan Abdullah, W.A.T.

ASM Science Journal, 2012;6(2):138-143.
MyJurnal

Finding a proper transition structure for the peptide bond formation process can lead to a better understanding of the role of the ribosome in catalyzing this reaction. A potential energy surface scan was performed on the ester bond dissociation of the P-site aminoacyl-tRNA and the peptide bond formation of P-site and A-site amino acids. The full fragment of initiator tRNAi met attached to both cognate (met) and non-cognate (ala) amino acids as the P-site substrate and the methionine as the A-site amino acid was used in this study. Due to the large size of tRNA, ONIOM calculations were used to reduce the computational cost. This study illustrated that the rate of peptide bond formation was reduced for misacylated tRNA without the presence of ribosomal bases. This demonstrated that there were indeed specific structural interactions involving the amino acid side chain within the tRNAi met.

Matched MeSH terms: Amino Acids
Fulltext Differential scanning calorimetry as tool in observing thermal and storage stability of recombinant bromelain

Nurul, A.I., Azura, A.

International Food Research Journal, 2012;19(2):727-731.
MyJurnal

Knowledge about the thermal and storage behavior of produced protein is important for the purpose of storage, transport and shelve life during industrial application. Recombinant bromelain thermal and storage stability were measured and compared to the commercial bromelain using Differential Scanning Calorimetry (DSC). Recombinant bromelain is more stable than commercial bromelain at higher temperature but the stability was reduced after 7 days of storage at 4oC. Higher energy is needed to break the bond between amino acid chains in recombinant bromelain as shown by the enthalpy obtained, suggesting that recombinant bromelain has good protein structure and conformation compared to commercial.

Matched MeSH terms: Amino Acids
Fulltext Net charge, hydrophobicity and specific amino acids contribute to the activity of antimicrobial peptides

Jindal MH, Le CF, Mohd Yusof MY, Sekaran SD

JUMMEC, 2014;17(1):1-7.
MyJurnal

Antimicrobial peptides (AMPs) have gained increasing attention as a potential candidate in the development of novel antimicrobial agent. Designing AMPs with enhanced antimicrobial activity while reducing the cell toxicity level is desired especially against the antibiotic-resistant microbes. Various approaches towards the design of AMPs have been described and physicochemical properties of AMPs represent the primary factors determining the antimicrobial potency of AMPs. The most common parameters include net charge and hydrophobicity, which greatly influence the antimicrobial activity of AMPs. Moreover, certain amino acids would have critical importance in affecting the antimicrobial activity as well as cell cytotoxicity of AMPS. In this review, net charge, hydrophobicity, and specific amino acid residues were discussed as factors contributing to the antimicrobial activity of AMPs.

Matched MeSH terms: Amino Acids
Potential of Producing Flavonoids Using Cyanobacteria As a Sustainable Chassis

Jin H, Wang Y, Zhao P, Wang L, Zhang S, Meng D, et al.

J Agric Food Chem, 2021 Oct 27;69(42):12385-12401.
PMID: 34649432 DOI: 10.1021/acs.jafc.1c04632

Numerous plant secondary metabolites have remarkable impacts on both food supplements and pharmaceuticals for human health improvement. However, higher plants can only generate small amounts of these chemicals with specific temporal and spatial arrangements, which are unable to satisfy the expanding market demands. Cyanobacteria can directly utilize CO2, light energy, and inorganic nutrients to synthesize versatile plant-specific photosynthetic intermediates and organic compounds in large-scale photobioreactors with outstanding economic merit. Thus, they have been rapidly developed as a "green" chassis for the synthesis of bioproducts. Flavonoids, chemical compounds based on aromatic amino acids, are considered to be indispensable components in a variety of nutraceutical, pharmaceutical, and cosmetic applications. In contrast to heterotrophic metabolic engineering pioneers, such as yeast and Escherichia coli, information about the biosynthesis flavonoids and their derivatives is less comprehensive than that of their photosynthetic counterparts. Here, we review both benefits and challenges to promote cyanobacterial cell factories for flavonoid biosynthesis. With increasing concerns about global environmental issues and food security, we are confident that energy self-supporting cyanobacteria will attract increasing attention for the generation of different kinds of bioproducts. We hope that the work presented here will serve as an index and encourage more scientists to join in the relevant research area.

Matched MeSH terms: Amino Acids, Aromatic
Fulltext Physicochemical properties of mud clam (Polymesoda erosa) hydrolysates obtained using different microbial enzymes

Normah, I., Noorasma, M.

International Food Research Journal, 2015;22(3):1103-1111.
MyJurnal

Physicochemical properties of mud clam (Polymesoda erosa) hydrolysate produced using two microbial enzymes; alcalase and flavourzyme were determined. Hydrolysis using alcalase at 20.28% degree of hydrolysis (DH) resulted in 25.06 % yield and 45.37% protein while flavourzyme hydrolysis showed 22.93 % DH, 46.67 % protein and 30.68 % yield. Both hydrolysates were yellowish. Better emulsifying properties, foaming properties and water and oil holding capacity were exhibited by flavourzyme hydrolysate compared to the alcalase hydrolysate. However, in terms of amino acid composition, alcalase hydrolysate contained higher amino acid composition (75.06%) than flavourzyme hydrolysate (62.37%). The study suggested that mud clam hydrolysate had the potential to be used in food formulations for human consumption.

Matched MeSH terms: Amino Acids
The effect of alkaline extraction and drying techniques on the physicochemical, structural properties and functionality of rice bran protein concentrates

Abd Rahim FN, Wan Ibadullah WZ, Saari N, Brishti FH, Mustapha NA, Ahmad N, et al.

Int J Biol Macromol, 2023 Jul 01;242(Pt 3):124908.
PMID: 37217045 DOI: 10.1016/j.ijbiomac.2023.124908

Rice bran protein concentrates (RBPC) were extracted using mild alkaline solvents (pH: 8, 9, 10). The physicochemical, thermal, functional, and structural aspects of freeze-drying (FD) and spray-drying (SD) were compared. FD and SD of RBPC had porous and grooved surfaces, with FD having non-collapsed plates and SD being spherical. Alkaline extraction increases FD's protein concentration and browning, whereas SD inhibits browning. According to amino acid profiling, RBPC-FD9's extraction optimizes and preserves amino acids. A tremendous particle size difference was prominent in FD, thermally stable at a minimal maximum of 92 °C. Increased pH extraction gives FD greater exposal surface hydrophobicity and positively relates to denaturation enthalpy. Mild pH extraction and drying significantly impacted solubility, improved emulsion properties, and foaming properties of RBPC as observed in acidic, neutral, and alkaline environments. RBPC-FD9 and RBPC-SD10 extracts exhibit outstanding foaming and emulsion activity in all pH conditions, respectively. Appropriate drying selection, RBPC-FD or SD potentially employed as foaming/emulsifier agent or meat analog.

Matched MeSH terms: Amino Acids
Mechanistic insights into the lignin dissolution behavior in amino acid based deep eutectic solvents

Zhang Y, Ren H, Li B, Udin SM, Maarof H, Zhou W, et al.

Int J Biol Macromol, 2023 Jul 01;242(Pt 2):124829.
PMID: 37210053 DOI: 10.1016/j.ijbiomac.2023.124829

Deep eutectic solvents (DESs) composed by amino acids (L-arginine, L-proline, L-alanine) as the hydrogen bond acceptors (HBAs) and carboxylic acids (formic acid, acetic acid, lactic acid, levulinic acid) as hydrogen bond donors (HBDs) were prepared and used for the dissolution of dealkaline lignin (DAL). The mechanism of lignin dissolution in DESs was explored at molecular level by combining the analysis of Kamlet-Taft (K-T) solvatochromic parameters, FTIR spectrum and density functional theory (DFT) calculations of DESs. Firstly, it was found that the formation of new hydrogen bonds between lignin and DESs mainly drove the dissolution of lignin, which were accompanied by the erosion of hydrogen bond networks in both lignin and DESs. The nature of hydrogen bond network within DESs was fundamentally determined by the type and number of functional groups in both HBA and HBD, which affected its ability to form hydrogen bond with lignin. One hydroxyl group and carboxyl group in HBDs provided active protons, which facilitated proton-catalyzed cleavage of β-O-4, thus enhancing the dissolution of DESs. The superfluous functional group resulted in more extensive and stronger hydrogen bond network in the DESs, thus decreasing the lignin dissolving ability. Moreover, it was found that lignin solubility had a closed positive correlation with the subtraction value of α and β (net hydrogen donating ability) of DESs. Among all the investigated DESs, L-alanine/formic acid (1:3) with the strong hydrogen-bond donating ability (acidity), weak hydrogen-bond accepting ability (basicity) and small steric-hindrance effect showed the best lignin dissolving ability (23.99 wt%, 60 °C). On top of that, the value of α and β of L-proline/carboxylic acids DESs showed some positive correlation with the global electrostatic potential (ESP) maxima and minima of the corresponding DESs respectively, indicating the analysis of ESP quantitative distributions of DESs could be an effective tool for DESs screening and design for lignin dissolution as well as other applications.

Matched MeSH terms: Amino Acids
tLyp-1: A peptide suitable to target NRP-1 receptor

Larue L, Kenzhebayeva B, Al-Thiabat MG, Jouan-Hureaux V, Mohd-Gazzali A, Wahab HA, et al.

Bioorg Chem, 2023 Jan;130:106200.
PMID: 36332316 DOI: 10.1016/j.bioorg.2022.106200

Targeting vascular endothelial growth factor receptor (VEFGR) and its co-receptor neuropilin-1 (NRP-1) is an interesting vascular strategy. tLyp-1 is a tumor-homing and penetrating peptide of 7 amino acids (CGNKRTR). It is a truncated form of Lyp-1 (CGNKRTRGC), which is known to target NRP-1 receptor, with high affinity and specificity. It is mediated by endocytosis via C-end rule (CendR) internalization pathway. The aim of this study is to evaluate the importance of each amino acid in the tLyp-1 sequence through alanine-scanning (Ala-scan) technique, during which each of the amino acid in the sequence was systematically replaced by alanine to produce 7 different analogues. In silico approach through molecular docking and molecular dynamics are employed to understand the interaction between the peptide and its analogues with the NRP-1 receptor, followed by in vitro ligand binding assay study. The C-terminal Arg is crucial in the interaction of tLyp-1 with NRP-1 receptor. Substituting this residue dramatically reduces the affinity of this peptide which is clearly seen in this study. Lys-4 is also important in the interaction, which is confirmed via the in vitro study and the MM-PBSA analysis. The finding in this study supports the CendR, in which the presence of R/K-XX-R/K motif is essential in the binding of a ligand with NRP-1 receptor. This presented work will serve as a guide in the future work pertaining the development of active targeting agent towards NRP-1 receptor.

Matched MeSH terms: Amino Acids
Need analysis of a dietary application among caregivers of patients with disorders of amino acid metabolism (AAMDs): A mixed-method approach

Lim JY, Ali NM, Rajikan R, Amit N, Hamid HA, Leong HY, et al.

Int J Med Inform, 2023 Sep;177:105120.
PMID: 37295139 DOI: 10.1016/j.ijmedinf.2023.105120

BACKGROUND: A dietary application can assist the caregivers of AAMDs children in auto-calculating the protein intake, hence improving dietary compliance. However, existing dietary application for patients with AAMDs only focus on delivering the nutritional content of food and monitoring the dietary intake but were lacking in other educational components.
OBJECTIVE: To assess the uses, needs and preferences towards a dietary application among the caregivers of AAMDs patients.
METHODS: We conducted a mixed-method study comprising focus group discussion (FGD) and a quantitative questionnaire survey among caregivers of patients aged between 6-month-old to 18-year-old with AAMDs who are receiving active treatment, both medical and dietetic treatment in the genetic clinic, Hospital Kuala Lumpur (HKL).
RESULTS: A total of 76 and 20 caregivers participated in the survey and FGD respectively. All the caregivers (100%) possessed a smartphone and most of the caregivers (89.5%) had the experience of using smartphone or other technological devices to search for health or medical information. However, majority of the participants were not aware of the existence of any web-based or mobile application related to AAMDs (89.5%). While for the qualitative part, three themes emerged: (1) experience with current source of information; (2) needs for supporting self-management educational contents and needs for technological design application. Most of the caregivers used the nutritional booklet as sources of reference but some of them searched for web-based information. Features perceived by the caregivers included a digital food composition database, sharing diet recall with healthcare providers, self-monitoring diet intake as well as low protein recipes. Besides that, user-friendly and ease to use were also perceived as the important features by the caregivers.
CONCLUSION: The identified features and needs by the caregivers should be integrated into the design of the apps to promote acceptance and usage.

Matched MeSH terms: Amino Acids
Validation of a reverse-phase high-performance liquid chromatography method for the determination of amino acids in gelatins by application of 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate reagent

Azilawati MI, Hashim DM, Jamilah B, Amin I

J Chromatogr A, 2014 Aug 1;1353:49-56.
PMID: 24797394 DOI: 10.1016/j.chroma.2014.04.050

In-house method validation was conducted to determine amino acid composition in gelatin by a pre-column derivatization procedure with the 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate reagent. The analytical parameters revealed that the validated method was capable of selectively performing a good chromatographic separation for 18 amino acids in less than 40 min; the overall detection and quantitation limit for amino acids fell into ranges of 5.68-12.48 and 36.0-39.0 pmol/μl, respectively; the matrix effect was not observed, and the linearity range was 37.5-1000 pmol/μl. The accuracy (precision and recovery) analyses of the method were conducted under repeatable conditions on different days in random order. Method precision revealed by HorRat values was significantly less than 2, except for histidine with a precision of 2.19, and the method recoveries had a range of 80-115% except for alanine which was recovered at 79.4%. The findings were reproducible and accurately defined, and the method was found to be suited to routine analysis of amino acid composition in gelatin-based ingredients.

Matched MeSH terms: Amino Acids/analysis*; Amino Acids/chemistry
Microsporum fulvum IBRL SD3: as novel isolate for chicken feathers degradation

Darah I, Nur-Diyana A, Nurul-Husna S, Jain K, Lim SH

Appl Biochem Biotechnol, 2013 Dec;171(7):1900-10.
PMID: 24013862 DOI: 10.1007/s12010-013-0496-4

Keratinous wastes have increasingly become a problem and accumulate in the environment mainly in the form of feathers, generated mainly from a large number of poultry industries. As keratins are very difficult to degrade by general proteases, they pose a major environmental problem. Therefore, microorganisms which would effectively degrade keratins are needed for recycling such wastes. A geophilic dermatophyte, Microsporum fulvum IBRL SD3 which was isolated from a soil sample collected from a chicken feather dumping site using a baiting technique, was capable to produce keratinase significantly. The crude keratinase was able to degrade whole chicken feathers effectively. The end product of the degradation was protein that contained essential amino acids and may have potential application in animal feed production. Thus, M. fulvum could be a novel organism to produce keratinase for chicken feathers degradation.

Matched MeSH terms: Amino Acids/biosynthesis; Amino Acids/metabolism
Dissolution and delignification of bamboo biomass using amino acid-based ionic liquid

Muhammad N, Man Z, Bustam MA, Mutalib MI, Wilfred CD, Rafiq S

Appl Biochem Biotechnol, 2011 Oct;165(3-4):998-1009.
PMID: 21720837 DOI: 10.1007/s12010-011-9315-y

In the present work, the dissolution of bamboo biomass was tested using a number of ionic liquids synthesized in laboratory. It was observed that one of the synthesized amino acid-based ionic liquids, namely 1-ethyl-3-methylimidazolium glycinate, was capable of dissolving the biomass completely. The dissolved biomass was then regenerated using a reconstitute solvent (acetone/water) and was characterized using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The results were compared to preconditioned bamboo biomass. The regenerated biomass was found to have a more homogenous macrostructure, which indicates that the crystalline form and structure of its cellulose has changed from type Ι to type ΙΙ during the dissolution and regeneration process.

Matched MeSH terms: Amino Acids/metabolism*; Amino Acids/chemistry
Alterations in juvenile diploid and triploid African catfish skin gelatin yield and amino acid composition: Effects of chlorpyrifos and butachlor exposures

Karami A, Karbalaei S, Zad Bagher F, Ismail A, Simpson SL, Courtenay SC

Environ Pollut, 2016 Aug;215:170-177.
PMID: 27182978 DOI: 10.1016/j.envpol.2016.05.014

Skin is a major by-product of the fisheries and aquaculture industries and is a valuable source of gelatin. This study examined the effect of triploidization on gelatin yield and proximate composition of the skin of African catfish (Clarias gariepinus). We further investigated the effects of two commonly used pesticides, chlorpyrifos (CPF) and butachlor (BUC), on the skin gelatin yield and amino acid composition in juvenile full-sibling diploid and triploid African catfish. In two separate experiments, diploid and triploid C. gariepinus were exposed for 21 days to graded CPF [mean measured: 10, 16, or 31 μg/L] or BUC concentrations [Mean measured: 22, 44, or 60 μg/L]. No differences in skin gelatin yield, amino acid or proximate compositions were observed between diploid and triploid control groups. None of the pesticide treatments affected the measured parameters in diploid fish. In triploids, however, gelatin yield was affected by CPF treatments while amino acid composition remained unchanged. Butachlor treatments did not alter any of the measured variables in triploid fish. To our knowledge, this study is the first to investigate changes in the skin gelatin yield and amino acid composition in any animal as a response to polyploidization and/or contaminant exposure.

Matched MeSH terms: Amino Acids/analysis; Amino Acids/metabolism*
Comparison of free amino acids, antioxidants, soluble phenolic acids, cytotoxicity and immunomodulation of fermented mung bean and soybean

Ali NM, Yeap SK, Yusof HM, Beh BK, Ho WY, Koh SP, et al.

J Sci Food Agric, 2016 Mar 30;96(5):1648-58.
PMID: 26009985 DOI: 10.1002/jsfa.7267

BACKGROUND: Mung bean and soybean have been individually reported previously to have antioxidant, cytotoxic and immunomodulatory effects, while fermentation is a well-known process to enhance the bioactive compounds that contribute to higher antioxidant, cytotoxic and immunomodulation effects. In this study, the free amino acids profile, soluble phenolic acids content, antioxidants, cytotoxic and immunomodulatory effects of fermented and non-fermented mung bean and soybean were compared.
RESULTS: Fermented mung bean was recorded to have the highest level of free amino acids, soluble phenolic acids (especially protocatechuic acid) and antioxidant activities among all the tested products. Both fermented mung bean and soybean possessed cytotoxicity activities against breast cancer MCF-7 cells by arresting the G0/G1 phase followed by apoptosis. Moreover, fermented mung bean and soybean also induced splenocyte proliferation and enhanced the levels of serum interleukin-2 and interferon-γ.
CONCLUSION: Augmented amounts of free amino acids and phenolic acids content after fermentation enhanced the antioxidants, cytotoxicity and immunomodulation effects of mung bean and soybean. More specifically, fermented mung bean showed the best effects among all the tested products. This study revealed the potential of fermented mung bean and soybean as functional foods for maintenance of good health.

Matched MeSH terms: Amino Acids/metabolism; Amino Acids/chemistry*
Formation and reduction of 5-hydroxymethylfurfural at frying temperature in model system as a function of amino acid and sugar composition

Kavousi P, Mirhosseini H, Ghazali H, Ariffin AA

Food Chem, 2015 Sep 1;182:164-70.
PMID: 25842323 DOI: 10.1016/j.foodchem.2015.02.135

5-Hydroxymethylfurfural (HMF) is formed during heat treatment of carbohydrate-containing foods, especially in a deep-fat frying process. This study aimed to investigate the effect of amino acids on the formation and reduction of HMF from glucose, fructose and sucrose at frying temperature in model systems containing binary mixtures of an amino acid and a sugar in equal concentrations (0.3M). The results revealed that the formation of HMF from sugars accelerated in the presence of acidic amino acids (i.e. glutamic and aspartic acids). Conversely, the presence of basic amino acids (i.e. lysine, arginine and histidine) led to reduced concentrations of HMF to non-detectable levels in model systems. The results showed that both pH and heating time significantly affected the formation of HMF from fructose in the presence of glutamic acid. In this regard, a higher amount of HMF was formed at lower pH.

Matched MeSH terms: Amino Acids/analysis*; Amino Acids/chemistry
Substrate specificity of king cobra (Ophiophagus hannah) venom L-amino acid oxidase

Tan NH, Saifuddin MN

Int. J. Biochem., 1991;23(3):323-7.
PMID: 2044840

1. Substrate specificity of purified king cobra (Ophiophagus hannah) venom L-amino acid oxidase was investigated. 2. The enzyme was highly specific for the L-enantiomer of amino acid. Effective oxidation of L-amino acid by the enzyme requires the presence of a free primary alpha-amino group but the alpha-carboxylate group is not as critical for the catalysis. 3. The enzyme was very active against L-Lys, L-Phe, L-Leu, L-Tyr, L-Tryp, L-Arg, L-Met, L-ornithine, L-norleucine and L-norvaline and moderately active against L-His, L-cystine and L-Ileu. Other L-amino acids were oxidized slowly or not oxidized. 4. The data suggest the presence of a side chain binding site in the enzyme, and that the binding site comprises at least five 'subsites': the hydrophobic subsites a, b and c; and the two 'amino' binding subsites d and e. Subsite b appears to be able to accommodate two methylene/methyl carbons.

Matched MeSH terms: Amino Acids/metabolism; Amino Acids/chemistry
Fulltext Modulation of Crustacean Innate Immune Response by Amino Acids and Their Metabolites: Inferences From Other Species

Huang Z, Aweya JJ, Zhu C, Tran NT, Hong Y, Li S, et al.

Front Immunol, 2020;11:574721.
PMID: 33224140 DOI: 10.3389/fimmu.2020.574721

Aquaculture production of crustaceans (mainly shrimp and crabs) has expanded globally, but disease outbreaks and pathogenic infections have hampered production in the last two decades. As invertebrates, crustaceans lack an adaptive immune system and mainly defend and protect themselves using their innate immune system. The immune system derives energy and metabolites from nutrients, with amino acids constituting one such source. A growing number of studies have shown that amino acids and their metabolites are involved in the activation, synthesis, proliferation, and differentiation of immune cells, as well as in the activation of immune related signaling pathways, reduction of inflammatory response and regulation of oxidative stress. Key enzymes in amino acid metabolism have also been implicated in the regulation of the immune system. Here, we reviewed the role played by amino acids and their metabolites in immune-modulation in crustaceans. Information is inferred from mammals and fish where none exists for crustaceans. Research themes are identified and the relevant research gaps highlighted for further studies.

Matched MeSH terms: Amino Acids/immunology*; Amino Acids/metabolism

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