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PYCR1 is a universal housekeeping enzyme which catalyzes the NAD(P)H-dependent conversion of pyrroline-5-carboxylate to proline. PYCR1 enzyme also takes a physiologic part in the generation of NADP(+) in certain cell types. PYCR1 forms a homopolymer and localizes to the mitochondrion. Mutations in PYCR1 are the source of cutis laxa autosomal recessive type 2B (ARCL2B).

MAT1A catalyzes a two-step reaction that involves the transfer of the adenosyl moiety of ATP to methionine to form S-adenosylmethionine and tripolyphosphate, which is subsequently cleaved to PPi and Pi. S-adenosylmethionine is the source of methyl groups for most biological methylations. MAT1A is found as a homotetramer (MAT I) or a homodimer (MAT III) whereas a third form, MAT II (gamma), is encoded by the MAT2A gene. Mutations in MAT1A gene are associated with methionine adenosyltransferase deficiency. MAT1A expression also correlates with a differentiated phenotype, whereas liver cells expressing MAT2A present a dedifferentiated phenotype and lowered AdoMet synthesis. Likewise, NFκB and TNFα cause a switch from MAT1A to MAT2A expression in human hepatocellular carcinoma (HCC), which facilitates cancer cell growth.

Angiotensin is an oligopeptide in the blood that causes vasoconstriction, increased blood pressure, and release of aldosterone from the adrenal cortex. It is a powerful dipsogen. It is derived from the precursor molecule angiotensinogen, a serum globulin produced in the liver. It plays an important role in the renin-angiotensin system.
The protein encoded by this gene, pre-angiotensinogen or angiotensinogen precursor, is expressed in the liver and is cleaved by the enzyme renin in response to lowered blood pressure. The resulting product, angiotensin I is then cleaved by angiotensin converting enzyme (ACE) to generate the physiologically active enzyme angiotensin II. The protein is involved in maintaining blood pressure and in the pathogenesis of essential hypertension and preeclampsia.

Mercaptopyruvate Sulfurtransferase (MPST) catalyzes the transfer of a sulfur ion from 3-mercaptopyruvate to cyanide or other thiol compounds. MPST might be involved in cysteine degradation and cyanide detoxification. The MPST enzyme is regulated by oxidative stress and thioredoxin. In oxidative stress conditions, the catalytic cysteine site is transformed to a sulfenate which inhibits the MPST enzyme activity. The reduced thioredoxin cleaves an intersubunit disulfide bond to activate the redox switch and reactivate the enzyme. A deficiency in MPST activity is implicated in a rare inheritable condition known as MCDU (mercaptolactate-cysteine disulfiduria).

DDT is an enzyme that catayzes the tautomerization of D-dopachrome to give 5,6-dihydroxyindole (DHI). DDT is part of the family of lyases, specifically the carboxy-lyases, which cleave carbon-carbon bonds. DDT shares a homologous amino acid sequence (33% identical) with MIF and has similar tautomerase activity. DDT functions a proinflammatory cytokine.

HPRT1 has a main part in the generation of purine nucleotides through the purine salvage pathway. HPRT1 primarily functions to salvage purines from degraded DNA to renewed purine synthesis. Therefore, it performs as a catalyst in the reaction between guanine and phosphoribosyl pyrophosphate to form GMP.

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.

Inositol monophosphatase1 (IMPA1) is responsible for the provision of inositol essential for synthesis of phosphatidylinositol and polyphosphoinositides. IMPA1 has a central role in the phosphatidylinositol signaling pathway by catalyzing the hydrolysis of inositol monophosphates. IMPA1 has been recognized as the pharmacological target for lithium action in the brain. The IMPA1 enzyme has a magnesium-dependent phosphatase activity and is inhibited by therapeutic concentrations of lithium. Inhibition of inositol monophosphate hydroylosis and ensuing depletion of inositol for phosphatidylinositol synthesis may perhaps explain the anti-manic and anti-depressive effects of lithium administered to treat bipolar disorder.

Glycogenin-1 (GYG1) is an enzyme involved in glycogen biosynthesis. GYG1 is the chief enzyme involved in glycogen polymerisation. Glycogenin-1 is vital for the function of self-glucosylates, using an inter-subunit mechanism, to form an oligosaccharide primer which acts as substrate for glycogen synthase. In addition, GYG1 has a role in regulating glycogen metabolism and the achievement of maximal glycogen levels in skeletal muscle. GYG1 mRNA and protein content and activity increase in the muscle during recovery from prolonged and exhaustive exercise. GYG1 is inactivated with glycogen catabolism which concurs with an increase in glycogenin gene expression as exercise and glycogenolysis advance. Glycogenin will remain covalently attached to the reducing end of the glycogen molecule.

LCAT is an extracellular cholesterol esterifying enzyme, lecithin-cholesterol acyltransferase. The esterification of cholesterol is required for cholesterol transport. LCAT is a essential enzyme in the extracellular metabolism of plasma lipoproteins.

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.

HPGD is the essential enzyme of prostaglandin degradation. 15-PGDH protein strongly decreases the biologic activity of these molecules by catalyzing the oxidation of the 15-hydroxyl group of prostaglandins to a keto group. GDH1 is involved in numerous physiologic and cellular processes, for instance inflammation.

Biotinidase also known BTD, belongs to the nitrilase superfamily, which contains 12 families of nitrilases, amidases, carbamylases, and N-acyltrasferases. BTD catalyzes the hydrolysis of biocytin, the product of biotin-dependent carboxylase degradation, to biotin and lysine. BTD has a vital regulatory part in chromatin/DNA function. Mutations in BTD protein lead to Biotinidase deficiency.

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.

Phosphoglycolate phosphatase (PGP) is discovered in all tissues including red cells, lymphocytes and cultured fibroblasts (at protein level). PGP is most active in skeletal muscle and cardiac muscle. The catalytic activity of PGP is 2-phosphoglycolate + H2O = glycolate + phosphate. Diseases associated with PGP include tardive dyskinesia and polycystic kidney disease.

Paraoxonase 2 (PON2) is a member of a multigene family whose genes share 65% identity at the amino acid level, and is expressed in a variety of tissues, including the pancreas. PON2 overexpression has been shown to lower the intracellular oxidative state and reduce the cells ability to oxidize LDL. PON2 is therefore implicated in the modulation of oxidative stress.

Caspase 3 Apoptosis-Related Cysteine Peptidase (CASP3) belongs to the cysteine-aspartic acid protease (caspase) family. Sequential activation of caspases plays a key role in the execution-phase of cell apoptosis. Caspases exist as inactive proenzymes which undergo proteolytic processing at conserved aspartic residues to generate 2 subunits, large and small, that dimerize to create the active enzyme. CASP3 protein cleaves and activates caspases 6, 7 and 9, and the protein itself is processed by caspases 8, 9 and 10. CASP3 is the leading caspase involved in the cleavage of amyloid-beta 4A precursor protein, which is linked with neuronal death in Alzheimer's disease. In addition, CASP3 is involved in the cleavage of huntingtin. CASP3 also cleaves and activates sterol regulatory element binding proteins (SREBPs) between the basic helix-loop-helix leucine zipper domain and the membrane attachment domain. CASP3 initiates cell adhesion in sympathetic neurons through RET cleavage.

SAE1 is part of the ubiquitin-activating E1 family of proteins and participates in the significant first step of the UBL1 conjugation pathway. Proteins conjugated to Ub are marked for progressive degradation by the 26S Proteasome. SAE1 acts as a UBLI E1 ligase mediating the ATP-dependent activation of UBL1. SAE1 binds with UBLE1A and UBLE1B to form a heterodimer which can bind UBL1. SAE1 is a dimeric enzyme that takes part as a E1 ligase for SUMO1, SUMO2, SUMO3, and probably SUMO4. SAE1 regulates ATP-dependent activation of SUMO proteins and formation of a thioester with a conserved cysteine residue on SAE2.

Prolactin is a neuroendocrine hormone synthesized primarily by the pituitary gland but also a variety of other cell types including the placenta, brain and uterus. Prolactin’s primary function is to promote and maintain lactation and also in breast cancer development, regulation of reproductive function and immunoregulation.

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.

DCXR catalyzes the NADPH-dependent reduction of numerous pentoses, tetroses, trioses, alpha-dicarbonyl molecules and L-xylulose. DCXR takes part in the uronate cycle of glucose metabolism. DCXR participates in the water absorption and cellular osmoregulation in the proximal renal tubules by producing xylitol, an osmolyte, thus preventing osmolytic stress from occurring in the renal tubules.

Glucose-6-phosphate isomerase (GPI) is a part of the GPI family whose members encode multifunctional phosphoglucose isomerase proteins involved in energy pathways. GPI is a dimeric enzyme which catalyzes the reversible isomerization of glucose-6-phosphate and fructose-6-phosphate. Mammalian GPI also functions as a tumor-secreted cytokine and an angiogenic factor (AMF) which stimulates endothelial cell motility. In addition, GPI is a neurotrophic factor (Neuroleukin) for spinal and sensory neurons. GPI performs in different capacities inside and outside the cell. In the cytoplasm, GPI is involved in glycolysis and gluconeogenesis, while outside the cell it acts as a neurotrophic factor for spinal and sensory neurons.
Defects in the GPI gene cause the nonspherocytic hemolytic anemia and a severe enzyme deficiency can be linked to hydrops fetalis, immediate neonatal death and neurological impairment.