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Carboxypeptidase B (EC 3.4.17.2) catalyzes hydrolysis of the basic amino acids lysine, arginine and ornithine from the C-terminal end of polypeptides. The Mw was found to be 34.5 kDa, optimun pH-7.9, and pI-6. Carboxypeptidase B is inhibited by arginine, lysine and ornithine. The enzyme is not inhibited by di-isopropylfluorophosphate (DFP), but it is inhibited by metal chelating agents, e.g., EDTA, 1,10-phenanthroline.

MGMT is an enzyme that repairs O-6-methylguanine, a mutagenic DNA base damaged by endogenous and environmental alkylating agents and takes part in the cellular defense against the biological effects of O-6-methylguanine in DNA. MGMT repairs alkylated guanine in DNA by stoichiometrically transferring the alkyl group at the O-6 position to a cysteine residue in the enzyme. abnormal MGMT expression correlates with the prognosis in human solid cancers. MGMT decrease of expression is correlated with methylation. The human MGMT is a negative regulator of estrogen receptor-mediated transcription upon alkylation DNA damage. MGMT promoter hypermethylation plays an important role in the early steps of colorectal carcinogenesis. Abnormal promoter hypermethylation of MGMT gene is associated with oral squamous cell carcinomas.

AnsA is a cytoplasmic asparaginase from E.coli involved in intracellular asparagine utilization. E.coli has 2 L-asparaginases: the cytoplasmic type I form (ansA) and the periplasmic type II form (ansB). AnsA (Type L asparaginase) is constitutively expressed and is obligatory for the growth of the bacteria on asparagine as the sole nitrogen source.

PGAM1 is part of the phosphoglycerate mutase family. PGAM1 is an essential component of glucose and 2,3-BPGA (2,3-bisphosphoglycerate) metabolism and catalyzes the reversible reaction of 3-phosphoglycerate (3-PGA) to 2-phosphoglycerate (2-PGA) in the glycolytic pathway. PGAM1 is a dimeric enzyme containing, in different tissues, different proportions of a slow-migrating muscle (MM) isozyme, a fast-migrating brain (BB) isozyme, and a hybrid form (MB). PGAM1 mutations lead to muscle phosphoglycerate mutase deficiency, a.k.a. glycogen storage disease X.

DsbA appears to be necessary for correct formulation of disulfide bonds in exported proteins in vivo. DsbA is useful as a standard in immunoblotting. This protein catalyses the reduction and exchange of disulfide bonds and the oxidation of free sulfhydryl groups in vitro. It is the strongest oxidant of the thioredoxin superfamily. This thio/disulfide oxidoreductase is required for efficient disulfide bond formation in the periplasm of E. coli.

ATP-dependent Clp protease proteolytic subunit (CLPP) is a member of the peptidase family S14. CLPP cleaves peptides in a variety of proteins in a manner which requires ATP hydrolysis. CLPP being the catalytic core of the Clp proteolytic complex is commonly involved in many cellular processes via the regulation of intracellular protein quality. CLPP is responsible for a somewhat general and central housekeeping function rather than for the degradation of specific substrates.

MCEE catalyzes the interconversion of D- and L-methylmalonyl-CoA throughout the degradation of branched chain amino acids, odd chain-length fatty acids, and other metabolites. MCEE protein deficiency is an autosomal recessive inborn error of amino acid metabolism, involving valine, threonine, isoleucine and methionine. This organic aciduria can appear in the neonatal period with life-threatening metabolic acidosis, hyperammonemia, feeding difficulties, pancytopenia and coma.

NANS is a 359 amino acid protein that contains one AFP (antifreeze proteins)-like domain and functions in the biosynthesis of sialic acids. The ubiquitously expressed NANS enzymatically catalyzes the H2O-dependent formation of N-acetylneuraminic acid (Neu5Ac) and 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (KDN), both of which are sialic acids. NANS uses N-acetylmannosamine 6-phosphate as a substrate for Neu5Ac synthesis and mannose 6-phosphate as a substrate for KDN synthesis.

3-ketodihydrosphingosine reductase (KDSR) is a 332 amino acid multi-pass membrane protein which localizes to the ER and is a member of the short-chain dehydrogenases/reductases (SDR) family. KDSR is a secreted protein that is weakly expressed in hematopoietic tissue. Furthermore, KDSR catalyzes the reduction of 3-ketodihydrosphingosine (KDS) to dihydrosphingosine (DHS). The putative active site residues of KDSR are found on the cytosolic side of the endoplasmic reticulum membrane. Chromosomal rearrangement in the KDSR gene is a cause of follicular lymphoma, aka type II chronic lymphatic leukemia.

Luciferase is a general term for the class of oxidative enzymes used in bioluminescence and is distinct from a photoprotein. Luciferase catalyzes a bioluminescent reaction which involves the substrate luciferin as well as Mg2+ and ATP, produces green light with a wavelength of 562 nm. Luciferase from firefly is broadly used as a reporter for studying gene regulation and function, and for pharmaceutical screening.

Isopentenyl-diphosphate Delta-isomerase 2 (IDI2) is a member of the IPP isomerase type 1 family. IDI2 catalyzes the 1,3-allylic reorganization of the homoallylic substrate isopentenyl (IPP) to its extremely electrophilic allylic isomer, dimethylallyl diphosphate (DMAPP).

NAA10 is a member of the acetyltransferase family. NAA10 interacts with NAA15, HIF-1 and with the ribosome. In its binding to HIF-1, NAA10 functions as a protein acetyltransferase by regulating its stability. In various cell lines, NAA10 is downregulated in response to hypoxia. NAA10 is expressed during the course of the development of the brain.

6-PyruvoylTetrahydropterin Synthase is part of the family of lyases, specifically those carbon-oxygen lyases acting on phosphates. 6-PyruvoylTetrahydropterin Synthase catalyzes the elimination of inorganic triphosphate from dihydroneopterin triphosphate, which is the second and irreversible step in the biosynthesis of tetrahydrobiopterin from GTP. Tetrahydrobiopterin, is a necessary cofactor and regulator of a range of enzyme activities, including enzymes involved in serotonin biosynthesis and NO synthase activity. Mutations in 6-PyruvoylTetrahydropterin Synthase gene result in hyperphenylalaninemia.

Urate oxidase catalyzes the enzymatic oxidation (degrades) of uric acid into allantoin, an inactive and soluble metabolite, which is 5 to 10 fold more soluble than uric acid . Urate oxidase is an enzyme of the purine breakdown pathway that catalyses the oxidation of uric acid to allantoin. Uricase is present in numerous diverse organisms, but not in higher primates including human. Hyperuricaemia is most commonly associated with gout and also occurs in mammalians with malignancy, especially those with lymphoid malignancies due to rapid cell turnover and an increased rate of purine metabolism. Uricase is effective in the prevention and treatment of hyperuricaemia in mammalians with malignancy and in those who have undergone transplantation. It appears to act rapidly, safely and induces a more dramatic decrease in plasma levels of uric acid.

GPT catalyzes the reversible transamination between alanine and 2-oxoglutarate to create pyruvate and glutamate. GPT has a crucial part in the intermediary metabolism of glucose and amino acids. GPT is broadly used as an indicator of liver reliability or hepatocellular destruction in clinical tests.

GARS is an (alpha)2 dimer which is a member of the class II family of tRNA synthetases. GARS is a glycyl-tRNA synthetase, one of the aminoacyl-tRNA synthetases which charge tRNAs with their cognate amino acids. GARS catalyzes the attachment of glycine to tRNA(Gly). In addition, GARS is able to produce diadenosine tetraphosphate (Ap4A), which is a universal pleiotropic signaling molecule required for cell regulation pathways, by direct condensation of two ATPs. GARS has been demonstrated to be a target of autoantibodies in the human autoimmune diseases, polymyositis or dermatomyositis.

Branched Chain Amino-Acid Transaminase 2 (BCAT2) is a member of the class-IV pyridoxal-phosphate-dependent aminotransferase family. BCAT2 is a branched chain aminotransferase found in mitochondria. BCAT2 forms a dimer which catalyzes the first step in the production of the branched chain amino acids leucine, isoleucine, and valine. In addition, BCAT2 may actn as a transporter of branched chain alpha-keto acids.

Dehydrogenase/reductase SDR family member 4 (DHRS4) is a member of the short-chain dehydrogenases/reductases (SDR) family. DHRS4 reduces all trans retinal and 9-cis retinal. In addition, the DHRS4 protein can catalyze the oxidation of all trans retinol with NADP as cofactor, but with a much lower efficiency. Furthermore, DHRS4 reduces alkyl phenyl ketones and alpha dicarbonyl compounds with aromatic rings, such as pyrimidine 4 aldehyde, 3 benzoylpyridine, 4 benzoylpyridine, menadione and 4 hexanoylpyridine.

melA is a member of the glycosyl hydrolase 4 family. melA catalyze the hydrolysis of saccharides containing o-1,6,-galactoside bonds. melA catalyze the same reaction in E.coli, human and yeast but is found in different cellular sections: The E.coli melA is a cytoplasmic protein and the human and yeast melA are secretory proteins. Thus, even though the active enzyme from all three species has almost an equal molecular weight, structural resemblances, as well as dissimilarities, are probable.

Cystathionine gamma-lyase or cystathionase (CTH) is a member of the trans-sulfuration enzymes family. CTH is an enzyme which breaks down cystathionine into cysteine and alpha-ketobutyrate. The CTH catalyzes the last step in the transsulfuration pathway from methionine to cysteine. Glutathione synthesis in the liver is dependent upon the availability of cysteine. Mutations in the CTH gene cause cystathioninuria.

Dimethylglycine oxidase (DMGO) is a covalent flavoenzyme from Arthrobacter globiformis that catalyzes the oxidative demethylation of dimethylglycine to yield sarcosine, formaldehyde, and hydrogen peroxide. The N-terminal region binds FAD covalently so it is yellowish.

NQO2 is a flavoprotein that catalyzes the 2-electron reduction of diverse quinones, redox dyes, and the vitamin K menadione. NQO2 mainly uses dihydronicotinamide riboside (NRH) as the electron donor. NQO2 catalyzes the metabolic detoxification of quinones and their derivatives to hydroquinones. This detoxification process protects cells against quinone-induced oxidative stress, cytotoxicity and mutagenicity.

Glycerol dehydrogenase (GldA) catalyzes the NAD-dependent oxidation of glycerol to dihydroxyacetone (glycerone). The GldA protein allows microorganisms to use glycerol as a source of carbon under anaerobic conditions. Furthermore, in E.coli GldA has an imperative role by regulating the intracellular level of dihydroxyacetone by catalyzing the reverse reaction, i.e. the conversion of dihydroxyacetone into glycerol. GldA possesses an extensive substrate specificity, due to its ability to oxidize 1,2-propanediol and to reduce glycolaldehyde, methylglyoxal and hydroxyacetone into ethylene glycol, lactaldehyde and 1,2-propanediol, respectively.

Ubiquitin-like modifier activating enzyme 5 (UBA5) is a member of the ubiquitin-activating E1 family and UBA5 subfamily. Ubiquitin and ubiquitin-like proteins are recognized as covalently conjugated to various cellular substrates by a three-step enzymatic pathway. The ubiquitin-activating enzyme (E1) has a vital role in the first step of ubiquitination pathway to activate ubiquitin or ubiquitin-like proteins. UBA5 activates an ubiquitin-like protein, ubiquitin-fold modifier 1 (Ufm1), by forming a high-energy thioester bond. UBA5 is located primarily in cytoplasm, while it generally localizes to the nucleus in presence of SUMO2.