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GAPDH is a catalytic enzyme normally known to play a role in glycolysis. GAPDH exists as a tetramer composed of 36-kDa subunits and has a range of intracellular functions. GAPDH catalyzes the reversible reduction of 1,3-bisphosphoglycerate to glyceraldehyde 3-phosphophate in the presence of NADPH. Besides functioning as a glycolytic enzyme in cytoplasm, GAPDH has function in intracellular processes such as membrane fusion, microtubule bundling, phosphotransferase activity, nuclear RNA export, DNA replication and DNA repair. GAPDH catalyzes a vital energy-yielding step in carbohydrate metabolism, the reversible oxidative phosphorylation of glyceraldehyde-3-phosphate in the presence of inorganic phosphate and nicotinamide adenine dinucleotide (NAD). The enzyme exists as a tetramer of identical chains.

Isocitrate Dehydrogenase is an enzyme of the oxidoreductase class that catalyzes the conversion of isocitrate and NAD+ to yield 2-ketoglutarate, carbon dioxide, and NADH. It occurs in cell mitochondria. The enzyme requires Mg2+, Mn2+; it is activated by ADP, citrate, and Ca2+, and inhibited by NADH, NADPH, and ATP. The reaction is the key rate-limiting step of the citric acid (tricarboxylic) cycle.

ALDH2 is part of the aldehyde dehydrogenase family of proteins which catalyze the chemical transformation from acetaldehyde to acetic acid. ALDH2 is the second enzyme of the major oxidative pathway of alcohol metabolism. ALDH2 has 2 major liver isoforms: cytosolic and mitochondrial, which differ by their electrophoretic mobilities, kinetic properties, and subcellular localizations. Nearly all Caucasians have 2 major isozymes, whereas roughly 50% of Orientals have only the cytosolic isozyme, omitting the mitochondrial isozyme. The extremely higher rate of acute alcohol intoxication with Orientals compared to Caucasians is due to the fact of the absence of mitochondrial isozyme. ALDH2 has a low Km for acetaldehydes, and is localized in mitochondrial matrix.

E2 17-beta-dehydrogenase 8 (HSD17B8) is a member of the short-chain dehydrogenases/reductases (SDR) family. In mice, the HSD17B8 protein is a 17-beta-hydroxysteroid dehydrogenase which can regulate the concentration of biologically active estrogens and androgens. HSD17B8 is preferentially an oxidative enzyme and inactivates E2, testosterone, and DHT. However, the HSD17B8 enzyme has some reductive activity and can synthesize E2 from E1. HSD17B8 may have a role in biosynthesis of fatty acids in mitochondria.

PCBD1 enzyme takes part in phenylalanine hydroxylation. PCBD1 deficiency results in hyperphenylalaninemia. PCBD1 enzyme controls the homodimerization of HNF1. PCBD1 takes part in tetrahydrobiopterin biosynthesis. PCBD1 prevents the formation of 7-pterins and accelerate the formation of quinonoid-BH2. PCBD1 is a coactivator for HNF1A-dependent transcription.

TSTA3 is a NADP(H)-binding protein. TSTA3 catalyzes the two-step epimerase and the reductase reactions in GDP-D-mannose metabolism, converting GDP-4-keto-6-D-deoxymannose to GDP-L-fucose. GDP-L-fucose is the substrate of numerous fucosyltransferases that take part in the expression of several glycoconjugates, including blood group ABH antigens and developmental adhesion antigens.
Mutations in TSTA3 result in leukocyte adhesion deficiency, type II.

ACADL is a homotetramer belonging to the acyl-CoA dehydrogenase family. ACADL takes part in the catabolism of fatty acids and amino acids and is a key source of energy for the heart and skeletal muscle. Mutation in the ACADL gene results in non-ketotic hypoglycemia and hypotonia (muscle weakness).

ACADVL is an inner mitochondrial membrane enzyme that is part of the family of acyl-CoA dehydrogenases. ACADVL protein participates in lipid metabolism and has catalytic activity toward esters of long chain and very long chain fatty acids such as palmitoyl-CoA and stearoyl-CoA, and is involved in the first step of the fatty acid β-oxidation pathway. ACADVL deficiency in reduces myocardial fatty acid beta-oxidation and is related with cardiomyopathy.

ADH1C is a member of the zinc-containing alcohol dehydrogenase family which metabolizes a large assortment of substrates, such as ethanol, retinol, other aliphatic alcohols, hydroxysteroids, and lipid peroxidation products. ADH1 is a monomorphic and a key factor in fetal and infant livers, becoming less active in gestation and only weakly active during adulthood.

HAGH is a part of the glyoxalase family and a thiolesterase which hydrolyses S-lactoyl-glutathione to reduced glutathione and D-lactate. HAGH protein is a detoxifying enzyme of glycolysis byproduct methylglyoxal and a target of p63 and p73 and serves as a pro-survival factor of the p53 family. HAGH appears only as a monomer and binds two zinc ions per subunit.

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.

AKR1B1 is part of the aldo/keto reductase superfamily, which consists of more than 40 known enzymes and proteins. AKR1B1 catalyzes the reduction several aldehydes, including the aldehyde form of glucose, and thus involved in the development of diabetic complications by catalyzing the reduction of glucose to sorbitol. AKR1B1 catalyzes the NADPH-dependent reduction of a wide variety of carbonyl-containing compounds to their corresponding alcohols. Transgenic mice over expressing human aldose reductase show that AKR1B1 is a key player in ischemic injury and impairment of functional and metabolic recovery after ischemia. Aldose Reductase is an obligatory mediator of TNF-alpha signaling leading to an increase in the expression of adhesion molecules and increased binding of monocytes to the endothelium. AKR1B1 is a critical regulator of TNF-alpha-induced apoptotic signaling in endothelial cells.

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.

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.

NADH Dehydrogenase 1 Beta Subcomplex 4 (NDUFB4) is a member of the complex I NDUFB4 subunit family. NDUFB4 is a non-catalytic subunit of the multisubunit NADH:ubiquinone oxidoreductase, which is the first enzyme complex in the mitochondrial electron transport chain (complex I). Mammalian complex I is comprised of 45 different subunits and transfers electrons from NADH to ubiquinone.

DPP4 also called adenosine deaminase complexing protein-2, and T-cell activation antigen CD26 is a serine exopeptidase and complex enzyme that is expressed on the surface of most cell types. DPPIV is an intrinsic membrane glycoprotein and a serine exopeptidase that cleaves X-proline dipeptides from the N-terminus of polypeptides. DPP4 plays a role in t-cell activation. DPP4 is associated with intracellular signal transduction, apoptosis and involved in tumor biology. There are at least 63 substrates which can bind specifically to DPP4 enzyme including growth factors, chemokines, neuro peptides. Furthermore, DPP4 plays a major role in glucose metabolism by cleaving incretins such as glucose-dependent insulinotropic polypeptide (GIP) and GLP-1.

SULT2B1 catalyzes the sulfate conjugation of numerous hormones, neurotransmitters, drugs and xenobiotic compounds. Sulfonation enhances the water solubility of molecules, and therefore their renal excretion, however it can also result in bioactivation to form active metabolites. SULT2B1b is localized in the cytosol and nuclei of human cells. SULT2B1b is selective for the sulfation of 3beta-hydroxysteroids such as dehydroepiandrosterone and pregnenolone, and participates in cholesterol sulfation in human skin.

Small Ubiquitin-like Modifiers (SUMOs) are a family of small, related proteins that can be enzymatically attached to a target protein by a post-translational modification process termed sumoylation. Unlike ubiquitination, which targets proteins for degradation, sumoylation participates in a number of cellular processes, such as nuclear transport, transcriptional regulation, apoptosis, and protein stability. All SUMO proteins share the conserved ubiquitin domain and the C-terminal diglycine cleavage/attachment site. Human SUMO2, also known as Sentrin2 and SMT3B is synthesized as a 95 amino acid (aa), 11 kDa propeptide that contains a two aa C-terminal prosegment, and an 18 aa N-terminal protein interacting region (aa 33 -50). Following prosegment cleavage, the C-terminal glycine is enzymatically attached to a lysine on a target protein. Human SUMO2 shares 100% sequence identity to SUMO-2 from mouse. SUMO2 also has very high sequence homology to SUMO3 and SUMO4, 86 % and 85%, respectively. SUMO2 shares only 44% sequence identity to SUMO1.

Human PDE6D was initially identified as a fourth subunit of rod-specific cGMP phosphodiesterase, PDE6. PDE6D is an Oligomer composed of two catalytic chains (alpha and beta), an inhibitory chain (gamma) and the delta chain. PDE6D interacts with RPGR, ARL2 and ARL3. The catalytically active PDE6 is a heterodimer (αβ) that is controlled by two inhibitory γ subunits. Since PDE6D does not change the catalytic properties of PDEαβ, its function is still unanswered. PDE6D is expressed specifically in the retina.

The proteasome is a multicatalytic proteinase complex which holds an extremely organized 20S core structure shaped like a ring. The central structure is assembled from 4 rings of 28 non-identical subunits; 2 rings are composed of 7 alpha subunits and 2 rings are composed of 7 beta subunits. There is a high concentration of proteasomes all over the eukaryotic cells and their job is to cleave peptides in an ATP/ubiquitin-dependent procedure in a non-lysosomal pathway. PSMA3 encodes several of the peptidase T1A family which is a 20S core alpha subunit. Two alternative transcripts encoding diverse isoforms were recognized.

MDH1 catalyzes the reversible oxidation of malate to oxaloacetate, using the NAD/NADH cofactor system in the citric acid cycle. MDH1 is abundantly found in the cytoplasm and is involved in the malate-aspartate shuttle that functions in the metabolic coordination between cytosol and mitochondria. MDH1 regulates p53-dependent cell-cycle arrest and apoptosis in response to glucose deprivation.

SDF-1 (stromal cell-derived factor-1) is small cytokine belonging to the chemokine family that is officially designated Chemokine (C-X-C motif) ligand 12 (CXCL12). It is produced in two forms, SDF-1?/CXCL12a and SDF-1?/CXCL12b, by alternate splicing of the same gene. Chemokines are characterized by the presence of four conserved cysteines, which form two disulfide bonds. The CXCL12 proteins belong to the group of CXC chemokines, whose initial pair of cysteines are separated by one intervening amino acid. CXCL12 is strongly chemotactic for lymphocytes and has been implicated as an important cell co-ordinator during development. During embryogenesis it directs the migration of hematopoietic cells from foetal liver to bone marrow. Mice which were knocked-out for CXCL12 gene were lethal before the birth or within just 1 hour of life. As another role, CXCL12a alters also the electrophysiology of neurons. CXCL12 was shown to be expressend in many tissues in mice (including brain, thymus, heart, lung, liver, kidney, spleen and bone marrow).
The receptor for this chemokine is CXCR4, which was previously called fusin. This CXCL12-CXCR4 interaction used to be considered exclusive (unlike for other chemokines and their receptors), but recently it was suggested that CXCL12 is also bound by CXCR7 receptor.
The gene for CXCL12 is located on human chromosome 10. In human and mouse both CXCL12 and CXCR4 show high identity of sequence: 99% and 90%, respectively.

NAD (P) Dependent Steroid Dehydrogenase-Like (NSDHL) takes part in synthesis of cholesterol. NSDHL is involved in one of a few steps which convert lanosterol to cholesterol by removing a carbon atom and three hydrogen atoms (a methyl group). NSDHL is also a vital element of cell membranes and myelin, the fatty covering that insulates nerve cells.

BDH1 belongs to the short-chain dehydrogenase/reductase gene family. BDH1 forms a homotetrameric lipid-requiring enzyme of the mitochondrial membrane and has a specific necessity for phosphatidylcholine for optimal enzymatic activity. BDH1 catalyzes the interconversion of acetoacetate and (R)-3-hydroxybutyrate, the 2 main ketone bodies formed during fatty acid catabolism.