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Glutamyl-TRNA Amidotransferase, Subunit C also known as GATC allows the formation of properly charged Gln-tRNA(Gln) through the transamidation of misacylated Glu-tRNA(Gln) in the mitochondria. The reaction occurs in the attendance of glutamine and ATP through an activated gamma-phospho-Glu-tRNA(Gln). In addition, GATC is subunit of the heterotrimeric GatCAB amidotransferase (AdT) complex, composed of A (QRSL1), B (PET112) and C (GATC) subunits.

Uridine diphosphate glucose pyrophosphatase (NUDT14), is a part of the nudix hydrolase family. NUDT14 is a cytoplasmic protein which contains one nudix hydrolase domain and acts as the sugar donor in numerous glycosylation reactions, including those involved in the production of glycogen. NUDT14 hydrolyzes ADP-ribose into ribose 5-phosphate and AMP, and UDP-glucose to glucose 1-phosphate and UMP. NUDT14 is a homodimer which binds magnesium as a cofactor and is encoded by a gene located on human chromosome 14.

Ubiquitin carboxyl-terminal hydrolase isozyme L3 belongs to a gene family whose products hydrolyze small C-terminal adducts of ubiquitin to produce the ubiquitin monomer. UCHL3 takes part in the regulation of neuronal development and spermatogenesis and is associated to neurodegenerative diseases. UCHL3 has a 54% homology to UCHL1.

DLAT gene encodes component E2 of the multi-enzyme pyruvate dehydrogenase complex (PDC). PDC is located in the inner mitochondrial membrane and catalyzes the conversion of pyruvate to acetyl coenzyme A. The protein product of this gene, dihydrolipoamide acetyltransferase, takes acetyl groups created by the oxidative decarboxylation of pyruvate and transfers them to coenzyme A. Dihydrolipoamide acetyltransferase is the antigen for antimitochondrial antibodies which are found in about 95% of patients with the autoimmune liver disease primary biliary cirrhosis (PBC). In patients who suffer from this illness, activated T lymphocytes attack and destroy epithelial cells in the bile duct where this protein is abnormally distributed and overexpressed. PBC ultimately leads to cirrhosis and liver failure. Mutations in DLAT are also a cause of pyruvate dehydrogenase E2 deficiency which causes primary lactic acidosis in infancy and early childhood.

Short/branched chain specific acyl-CoA dehydrogenase (ACADSB) belongs to the acyl-CoA dehydrogenase family of enzymes which catalyze the dehydrogenation of acyl-CoA derivatives in the metabolism of fatty acids or branch chained amino acids. ACADSB catalyzes the degradation of L-isoleucine while having the highest affinity for (s)-2-methylbutyryl-CoA, isobutyryl-CoA and 2-methylhexanoyl-CoA as substrates. ACADSB may use valproyl-CoA as substrate. ACADSB gene defects cause the short/branched-chain acyl-CoA dehydrogenase deficiency (SBCADD), which is an autosomal recessive disorder characterized by an increase of 2-methylbutyrylglycine and 2-methylbutyrylcarnitine in blood and urine.

ADP-ribosylhydrolase like 2 (ADPRHL2) belongs to the ADP-ribosylglycohydrolase family. ADPRHL2 catalyzes the removal of ADP-ribose from ADP-ribosylated proteins. ADPRHL2, which is ubiquitously expressed, uses magnesium as a cofactor to catalyze the hydrolysis of poly (ADP-ribose) that is synthesized after DNA damage. Furthermore, ADPRHL2 has an essential role in the maintenance of normal neuronal cell function. The ADPRHL2 enzyme localizes to the mitochondria, in addition to the nucleus and cytoplasm.

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.

DLD is an L protein of the mitochondrial glycine cleavage system which is also a component of the pyruvate dehydrogenase complex, the alpha-ketoglutarate dehydrogenase complex, and the branched-chain alpha-keto acide dehydrogenase complex. DLD mutations were found in patients with E3-deficient maple syrup urine disease and lipoamide dehydrogenase deficiency.

DIM1 dimethyladenosine transferase 1 homolog (DIMT1) is a member of the methyltransferase superfamily. The DIMT1 enzyme specifically dimethylates 2 adjacent adenosines in the loop of a conserved hairpin near the 3'-end of 18S rRNA in the 40S particle. DIMT1 is restricted to the nucleolus.

GLO1 is involved in the catalysis and formation of S-lactoyl-glutathione from methylglyoxal condensation and reduced glutatione. GLO1 is linked to HLA and is localized to 6p21.3-p21.1, between HLA and the centromere. GLO1 enzyme is ubundantly expressed and present in numerous tumor cell lines, in which its concentration is often upregulated ubiquitisly. GLO1 is a major susceptible gene for autism in an ethnic Chinese population from Taiwan. GLO1 might be involved in the pathophysiology of mood disorders. GLO1 plays a role in the pathophysiology of mood disorders. Overexpression of GLO1 is associated with kidney tumor.

MTHFD2 plays a role as a homodimer which requires magnesium and inorganic phosphate. MTHFD2 has a pseudogene on chromosome 7 and owns 3 different enzymatic activities. Each of the activities catalyzes 1 of 3 sequential reactions in the interconversion of 1-carbon derivatives of tetrahydrofolate, which are substrates for methionine, thymidylate, and de novo purine syntheses.

UBE2D1 is a member of the ubiquitin-conjugating enzyme family. Ubiquitination involves at least 3 classes of enzymes: ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s) and ubiquitin-protein ligases (E3s). UBE2D1 is strongly related to a stimulator of iron transport (SFT), and is up-regulated in hereditary hemochromatosis. In addition, UBE2D1 functions in the ubiquitination of the tumor-suppressor protein p53 and the hypoxia-inducible transcription factor HIF1alpha by interacting with the E1 ubiquitin-activating enzyme and the E3 ubiquitin-protein ligases.

Mimitin (NDUFAF2) is a member of the complex I NDUFA12 subunit family.NADH dehydrogenase is an enzyme located in the inner mitochondrial membrane, which catalyzes the transfer of electrons from NADH to coenzyme Q (CoQ). NDUFAF2 is the "entry enzyme" of oxidative phosphorylation in the mitochondria. Mimitin protein functions as a molecular chaperone for mitochondrial complex I assembly.

Alanyl-tRNA synthetase is a member of the aminoacyl-tRNA synthetase family, key enzymes of protein biosynthesis which charge tRNA molecules with the respective amino acids. This 108 kDa protein is an autoantigen recognized by PL-12 antibodies which occur in a subset of patients with polymyositis and dermatomyositis. Preliminary data suggest that epitope spreading occurs in the autoimmune PL-12 response such that even antibodies to an isolated alanyl-tRNA molecule can develop.

Hexokinases phosphorylate glucose to produce glucose-6-phosphate, thus committing glucose to the glycolytic pathway. HK3 encodes hexokinase 3. Similar to hexokinases 1 and 2, this allosteric enzyme is inhibited by its product glucose-6-phosphate. Hexokinase3 lacks the hydrophobic N-terminal sequence critical for targeting to mitochondria. Hexpkinase3 may have anabolic functions, providing H6P for glycogen or lipid synthesis.

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.

Uroporphyrinogen III synthase (UROS) is an enzyme involved in the 4th step of porphyrin metabolism and in the conversion of hydroxymethyl bilane into uroporphyrinogen III. Defects in the UROS protein can cause molecular lesions which lead to the autosomal recessive Gunther disease, otherwise known as congenital erythropoietic porphyria (CEP).

Arylsulfatase G (ARSG) is a member of the sulfatase enzyme family. Sulfatases are enzymes which hydrolyze sulfate esters from sulfated steroids, carbohydrates, proteoglycans, and glycolipids. Sulfatases are involved in hormone biosynthesis, modulation of cell signaling, and degradation of macromolecules. The ARSG protein exhibits arylsulfatase activity at acidic pH, as is characteristic of lysosomal sulfatases. The Arylsulfatase G enzyme localizes in the lysosomes. ARSG is inhibited by phosphate, which forms a covalent bond with the active site 3-oxoalanine. Arylsulfatase G is widely expressed, having very low expression in the brain, lung, heart and skeletal muscle.

Phosphomannomutase 2 (PMM2) is a member of the eukaryotic PMM family. Phosphomannomutase 2 is involved in the synthesis of the GDP-mannose and dolichol-phosphate-mannose required for a number of critical mannosyl transfer reactions. PMM2 catalyzes the isomerization of mannose 6-phosphate to mannose 1-phosphate. PMM2 mutations are linked to congenital disorders of glycosylation (CDG)-Ia, an autosomal recessive disorder characterized by central nervous system dysfunction and multiorgan failure.

Thymidylate synthase catalyzes the methylation of deoxyuridylate to deoxythymidylate using 5,10-methylenetetrahydrofolate as a cofactor which maintains the dTMP (thymidine-5-prime monophosphate) pool vital for DNA replication and repair. Thymidylate synthase plays an important role as a cancer chemotherapeutic agent. Thymidylate synthase is the primary site of action for 5-fluoro-2-prime-deoxyuridine and several folate analogs.

Tartrate-resistant acid phosphatase type 5 (ACP5) is involved in osteopontin and bone sialoprotein dephosphorylation. ACP5 is an iron containing glycoprotein which catalyzes the conversion of orthophosphoric monoester to alcohol and orthophosphate. ACP5 expression seems to increase in some pathological states such as Gaucher and Hodgkin diseases, the hairy cell, the B-cell, and the T-cell leukemias. ACP5 is the most basic of the acid phosphatases and is the only form not inhibited by L(+)-tartrate.

Seryl-tRNA synthetase, cytoplasmic (SARS) is a member of the class-II aminoacyl-tRNA synthetase family. Aminoacyl-tRNA synthetases’ role is to catalyze the aminoacylation of tRNAs by their corresponding amino acids, as a result linking amino acids with tRNA-contained nucleotide triplets. The SARS enzyme catalyzes the attachment of serine to tRNA (Ser). SARS enzyme is probably able to aminoacylate tRNA (Sec) with serine, to form the misacylated tRNA L-seryl-tRNA (Sec), which will be then converted into selenocysteinyl-tRNA (Sec).

CNDP Dipeptidase 1, also known as CNDP1 is a member of the peptidase M20A family. CNDP1 Mannheim which is the shortest allelic form has been more common in the absence of nephropathy in addition to being associated with lower serum carnosinase levels. Furthermore, Carnosine inhibited the increased production of fibronectin as well as collagen type VI in podocytes and the increased production of TGF-beta in mesangial cells. Diabetic patients with the CNDP1 Mannheim variant are less at risk for nephropathy. In addition, on renal cells carnosine protects against the adverse effects of high glucose levels.

COMT catalyzes the transfer of a methyl group from S-adenosylmethionine (SAM) to catechol substrates such as the neurotransmitters. This O-methylation results in one of the main degradative pathways of the catecholamine transmitters. COMT COMT is located in the postsynaptic neuron and is involved in the metabolism of catechol estrogen drugs used in the treatment of hypertension, asthma, Parkinson disease and the inactivation of catecholamine neurotransmitters though enzymatic degradation. COMT appears in tissues in 2 forms, a soluble form and a membrane-bound form which differ in their N-termini. COMT inhibitors increase its availability and are used in the treatment of patients with Parkinson's disease.