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Antioxidant enzyme Glutathione S- Transferase (GST) is thought to do the primary cellular defense mechanism against reactive oxygen species. GST reduces lipid hydroperoxides through its Se-independent glutathione peroxidase activity. The enzyme also detoxifies lipid peroxidation end products such as 4-hydroxynonenal (4-HNE).
The soluble GST is a 26 kDa protein which occurs as a dimer in all aerobic organisms. Each monomer has two domains, one that binds GSH and is an /-structure similar to thioredoxin and the other, all helical, that binds the hydrophobic substrate. The GST -fusion protein expression system is a widely used recombinant protein expression system that allows a peptide or a regulatory protein domain to be expressed as a fusion to the C-terminus of Schistosoma japonicum GST. Fusion proteins also possess GST -enzymatic activity and can undergo dimerization similar to in vivo. The fusion protein can be purified via GST -affinity column chromatography. In most cases, the desired peptides or domains are removed from GST by applying a specific protease that recognizes and cleaves the linker between the protein domain and GST. The technique has been widely used to generate different kinds of proteins for crystallization, molecular immunology studies, the production of vaccines and studies involving protein-protein and protein-DNA interactions.

Dual specificity phosphatase 13 (DUSP13) is a member of the protein-tyrosine phosphatase family. DUSP13 cooperates with protein kinases to control cell proliferation and differentiation. DUSP13 is engaged in the regulation of meiosis and/or differentiation of testicular germ cells in the course of spermatogenesis. DUSP13 demonstrates intrinsic phosphatase activity towards both phospho-seryl/threonyl and -tyrosyl residues of myelin basic protein, with similar specific activities in vitro.

Uridine 5'-monophosphate synthase (UMPS), is a bifunctional enzyme that catalyzes the ultimate two steps of the de novo pyrimidine biosynthetic pathway. UMPS in eukaryotes links the orotate phosphoribosyltransferase and the orotidine-5’-monophosphate (OMP) decarboxylase activities into a single protein. The harmony of these 2 enzymes is assumed to be stabilized the catalytic centers as a result of the low molar concentration of the protein in mammalian cells.mutations in this gene are the reason of inherited orotic aciduria disease.

Glucosidase Beta Acid 3, also known as GBA3, hydrolyzes various types of glycosides. GBA3 takes part in a nonlysosomal catabolic pathway of glycosylceramide. GBA3 is a protein coding gene which acts as beta-glycosylceramidase.

Phosphoserine aminotransferase (PSAT1) catalyzes the conversion of 3-phosphohydroxypyruvate into 3-phosphoserine which is dephosphorylated consequently by phosphoserine phosphatase to form L-serine. PSAT1 is probably a phosphoserine aminotransferase, based on similarity to proteins in mouse, rabbit, and Drosophila. PSAT1 is expressed at high levels in the brain, liver, kidney and pancreas, and very weakly expressed in the thymus, prostate, testis and colon. Defects in the PSAT1 gene are the cause of phosphoserine aminotransferase deficiency (PSATD). PSATD is distinguished biochemically by low plasma and cerebrospinal fluid concentrations of serine and glycine and clinically by intractable seizures, acquired microcephaly, hypertonia, and psychomotor retardation.

Obg-like ATPase 1 (OLA1) acts as a negative regulator of the cellular antioxidant response independent of transcriptional processes. OLA1 curbs the antioxidant response via nontranscriptional mechanisms. OLA1 hydrolyzes ATP, and can also hydrolyze GTP with lower efficiency. OLA1 is clearly down-regulated by DNA damage-inducing agents. OLA1 is expressed in all tissues; however it is more abundant in the testis, liver, lung, and brain. OLA1 is overexpressed in a number of malignancies, including cancers of the colon, rectum, ovary, lung, stomach, and uterus.

Cytosolic and membrane-bound types of GST are encoded by 2 different supergene families. There are 8 classes of the soluble cytoplasmic mammalian GST: alpha, kappa, mu, omega, pi, sigma, theta and zeta. The mu class of enzymes functions in the detoxification of electrophilic compounds, including carcinogens, therapeutic drugs, environmental toxins and products of oxidative stress, by conjugation with glutathione. The genes encoding the mu class of enzymes are arranged in a gene cluster on chromosome 1p13.3 and aare highly polymorphic. These genetic differences can change an individual's resistance to carcinogens and toxins as well as affect the toxicity and efficacy of certain drugs. Null mutations of this class mu gene have been linked with the rise in a number of cancers.

Pyrroline-5-carboxylate reductase 2 isoform 1 (PYCR2) is a member of the pyrroline-5-carboxylate reductase family. PYCR2 protein catalyzes the conversion of pyrroline-5-carboxylate to proline, which is the last step in proline biosynthesis. The three substrates of the PYCR2 enzyme are L-proline, NAD+, and NADP+, while its four products are 1-pyrroline-5-carboxylate, NADH, NADPH, and H+.

Cathepsin D is synthesized as a 54kDa precursor, which is proteolytically processed to an intermediate 48kDa single chain, which matures into more stable 34kDa and 14kDa two chain form. It is an estrogen-regulated lysosomal protease that has been suggested to facilitate cancer cell migration and invasion by digesting the basement membrane, extracellular matrix, and xonnective tissue. Because of its mitogenic and proteolytic activities, it has been implicated as a prognostic marker in many tumor types. Cathepsin D is expressed in epithelial cells as well as in macrophages.

Epoxide Hydrolase 1 Microsomal (EPHX1) is a vital biotransformation enzyme which transfers epoxides from the degradation of aromatic compounds to trans-dihydrodiols that can be conjugated and excreted from the body. Epoxide hydrolase plays a role in both activation and detoxification of epoxides. Mutations in EPHX1 trigger preeclampsia, epoxide hydrolase deficiency or increased epoxide hydrolase activity.

FOLH1, also known as glutamate carboxypeptidase 2 (GCPII), is a single pass type 2 membrane protein which belongs to the peptidase M28 family. FOLH1 is highly produced in prostate epithelium. FOLH1 is also found in ovary, live, stomach, small intestine colon, urinary bladder, kidney, testis, and the capillary endothelium of a variety of tumours. Therefore, it plays a role in directed imaging and therapy of recurrent of metastatic disease. FOLH1 is a zinc metalloenzyme that resides in membranes and catalyses the hydrolysis of N-acetylaspartylglutamate to glutamate and N-acetylaspartate.

Carboxypeptidase A4 (CPA4) belongs to the carboxypeptidase A/B subfamily, and it is located in a cluster with 3 other family members on chromosome 7. CPA4 is a secreted, zinc-dependent metallocarboxypeptidase, which removes the C-terminal amino acid from peptides having a free C-terminal carboxyl group. CPA4 is a metalloprotease which may be involved in the histone hyperacetylation pathway. CPA4 are synthesized as zymogens which are activated by proteolytic cleavage.

NEDD8-activating enzyme E1 catalytic subunit (UBA3) is the catalytic subunit of the dimeric UBA3-NAE1 E1 enzyme, which belongs to the E1 ubiquitin-activating enzyme family. E1 activates NEDD8 by initially adenylating its C-terminal glycine residue with ATP, afterwards linking this residue to the side chain of the catalytic cysteine, generating a NEDD8-UBA3 thioester and free AMP. E1 at last transfers NEDD8 to the catalytic cysteine of UBE2M. The UBA3 enzyme connects with AppBp1, an amyloid beta precursor protein binding protein, to form a heterodimer, and at that point the enzyme complex activates NEDD8, a ubiquitin-like protein, which controls cell division, signaling and embryogenesis.

Aldolase C Fructose-Bisphosphate (ALDOC) belongs to the class I fructose-bisphosphate aldolase family. ALDOC is a glycolytic enzyme which catalyzes the reversible aldol cleavage of fructose-1,6-biphosphate and fructose 1-phosphate to dihydroxyacetone phosphate and either glyceraldehyde-3-phosphate or glyceraldehydes respectively. ALDOC is expressed exclusively in the hippocampus and Purkinje cells of the brain.

UDP Glycosyltransferase 8 (UGT8) is a member of the UDP-glycosyltransferase family. UGT8 catalyzes the transfer of galactose to ceramide, a crucial enzymatic step in the biosynthesis of galactocerebrosides, which are abundant sphingolipids of the myelin membrane of the central nervous system and peripheral nervous system.

TDP1 belongs to the phospholipase D family and contains two PLD phosphodiesterase domains. TDP1 is involved in repairing stalled topoisomerase I-DNA complexes by catalyzing the hydrolysis of the phosphodiester bond between the tyrosine residue of topoisomerase I and the 3-prime phosphate of DNA. TDP1 may also remove glycolate from single-stranded DNA containing 3-prime phosphoglycolate, suggesting a role in repair of free-radical mediated DNA double-strand breaks. Mutations in the TDP1 gene are linked to the disease spinocerebellar ataxia with axonal neuropathy (SCAN1).

Spermine synthase (SMS) is amember of the spermidine/spermine synthase family. SMS is an enzyme which converts spermidine into spermine. The SMS enzyme is essential for normal viability, growth and fertility involved in polyamine metabolism. Defects in the SMS gene are the cause of Snyder-Robinson syndrome (SRS), also known as X-linked mental retardation Snyder-Robinson type. SRS is categorized by moderate intellectual deficit, hypotonia, an unsteady gait, osteoporosis, kyphoscoliosis and facial asymmetry, its transmission is X-linked recessive.

MSRB2 is a member of the methionine sulfoxide reductases(MSRs) family which are antioxidant repair enzymes. MSRB2 protein catalyzes the decrease of free and protein-bound methionine sulfoxide to methionine. MSRB2 has a part in protecting against oxidative stress in numerous organs.

UbcH10 is an essential mediator of mitotic destruction events and cell cycle progression. It catalyzes the destruction of cyclins A and B in conjunction with the anaphase-promoting complex, and therefore, plays an important role in the control of the cell exit from mitosis This activity is essential at then end of mitosis for the inactivation of their partner kinase Cdc2 and exit from mitosis into G1 of the next cell cycle. In addition, UbcH10 bears homology to yeast PAS2, a gene that is essential for biogenesis of peroxisomes. UbcH10 is useful for in vitro ubiquitinylation reactions.

UBE2L6 belongs to the E2 ubiquitin-conjugating enzyme family. UBE2L6 enzyme is very similar in its primary structure to the enzyme encoded by UBE2L3 gene. UBE2L6 catalyzes the covalent attachment of ubiquitin to other proteins. UBE2L6 functions in the e6/e6-ap-induced ubiquitination of p53/tp53.

Carbonic anhydrase (carbonate dehydratase) is a family of metalloenzymes (enzymes that contain one or more metal atoms as a functional component of the enzyme) that catalyze the rapid (and reversible) conversion of carbon dioxide to bicarbonate and protons, a reaction that occurs rather slowly in the absence of a catalyst. Carbonic anhydrase greatly increases the rate of the reaction, with typical catalytic rates of the different forms of this enzyme ranging between 104 and 106 reactions per second. The active site of most carbonic anhydrases contains a zincion. CAIII is a cytoplasmic isoenzyme, but is released into the circulation following injury.

Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) belongs to the HAD-like hydrolase superfamily. LHPP is an exceptional enzyme which hydrolyzes not only oxygen-phosphorus bonds in inorganic pyrophosphate but also nitrogen-phosphorus bonds in phospholysine, phosphohistidine and imidodiphosphate in vitro. LHPP is expressed in the liver, kidney and moderately in the brain.

CA14 is a part of the Carbonic anhydrases family. Carbonic anhydrases (CAs) are a large family of zinc metalloenzymes which catalyze the reversible hydration of carbon dioxide. They present wide variety in tissue distribution and in their subcellular localization. CA14 is a type I membrane protein which shares highest sequence similarity with the other transmembrane CA isoform, CA XII. Nevertheless, they have different patterns of tissue-specific expression and therefore take different physiologic parts.

BPNT1 belongs to the magnesium-dependent, lithium-sensitive phosphomono-esterase superfamily. BPNT1 catalyzes the conversion of PAPS (adenosine 3'-phosphate 5' phosphosulfate) to APS (adenosine 5'-phosphosulfate) and the conversion of PAP (3'(2')-phosphoadenosine 5' phosphate) to AMP (adenosine 5'-phosphate) using magnesium as a cofactor. BPNT1 is expressed everywhere but at maximum levels in brain and kidney. BPNT1 is potently inhibited by lithium, a drug used for the treatment of manic depression and bipolar affective disorder, which suggests that BPNT1 has a possible role in the etiology of mood disorders.