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Creatine Kinase BB is a cytoplasmic enzyme involved in energy homeostasis. The encoded protein reversibly catalyzes the transfer of phosphate between ATP and various phosphogens such as creatine phosphate. It acts as a homodimer in brain as well as in other tissues, and as a heterodimer with a similar muscle isozyme in heart. The encoded protein is a member of the ATP:guanido phosphotransferase protein family. A pseudogene of this gene has been characterized.

Creatine Kinase, Mitochondrial 2 (CKMT2) is a member of the ATP:guanido phosphotransferase family. CKMT2 is responsible for the transfer of high energy phosphate from mitochondria to the cytosolic carrier, creatine. CKMT2 reversibly catalyzes the transfer of phosphate between ATP and various phosphogens (e.g. creatine phosphate). Creatine kinase isoenzymes have a principal role in energy transduction in tissues with large, variable energy demands, such as skeletal muscle, heart, brain and spermatozoa. Mitochondrial creatine kinase occurs in 2 different oligomeric forms: dimers and octamers, contrary to the exclusively dimeric cytosolic creatine kinase isoenzymes. The CKMT2 gene contains sequences homologous to a number of motifs which are shared among some nuclear genes encoding mitochondrial proteins and therefore may be crucial for the coordinated activation of these genes during mitochondrial biogenesis.

Dual Specificity Phosphatase 22, also known as DUSP22, is a part of the protein-tyrosine phosphatase family which holds 1 tyrosine-protein phosphatase domain. DUSP22 activates the Jnk signaling pathway and dephosphorylates and deactivates p38 and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK). DUSP22 interacts with MAPK1 and MAPK8.

SSU72 is an extremely conserved homologue of yeast Ssu72, a CTD phosphatase and a component of the polyadenylation/termination machinery. SSU72 interacts with TFIIB, Rb and DNAM-1 and operates to catalyze the dephosphorylation of target proteins, and taking part in RNA processing and termination via dephosphorylation of Pol II. SSU72 is found in multiple alternatively spliced isoforms.

GSTK1 is involved in cellular detoxification. GSTK1 is localized to the peroxisome and catalyzes the conjugation of the thiol group of glutathione (GSH) to the electrophilic groups of a broad range of hydrophobic substrates, leading to an easier removal of the latter from the cells.

GSTT1 belongs to a superfamily of proteins which catalyze the conjugation of reduced glutathione to a variety of electrophilic and hydrophobic compounds. GSTT1 is one of the GSTs’ four main classes: alpha, mu, pi and theta (which includes GSTT1 and GSTT2). GSTT1 is involved in activation and detoxification reactions and catalyzes the conjugation of industrial chemicals, such as epoxybutane, ethylene oxides, halomethane with glutathione. GSTT1 is found in erythrocytes, at low levels in the liver as well as in Clara and ciliated cells at the alveolar/bronchiolar junction in the lung.
The GSTT1 gene is deficient in 38% of the population. The GSTTI enzyme deficiency might influence the individual risk for development of acquired aplastic anemia and acute myeloid leukemia. The presence or absence of the GSTT1 gene is concurrent with GSST1+ (the conjugator) and GSTT1- (the non-conjugator) phenotypes correspondingly. The GSTT1+ phenotype is able to catalyze the glutathione conjugation of dichloromethane. GSTT1-null genotypes are seen as having a higher risk of developing leukoplakia. Germline genetic polymorphism in GSTT1 is linked to breast cancer.

Placental alkaline phosphatase (PLAP) is a membrane-associated siaglycoprotein enzyme normally present at high concentration in syncytiotrophoblasts within the placenta during the third trimester of gestation. The expression of PLAP was originally thought to be restricted to term placenta but a human PLAP-like variant has been described which shares more than 85% homology with PLAP itself. PLAP is expressed only in normal term placenta, endocervix and fallopian tube and also in ovarian and proximal gastrointestinal tumors. It is also commonly expressed in germ cell tumors and more recently described in seminomas.

PPIH is a part of the peptidyl-prolyl cis-trans isomerase (PPIase) family. PPIases catalyze the cis-trans isomerization of proline imidic peptide bonds in oligopeptides and increase protein folding. PPIH enzyme is a precise factor of the complex that comprises pre-mRNA processing factors PRPF3, PRPF4, and PRPF18, as well as U4/U5/U6 tri-snRNP. PPIH possess PPIase activity and acts as a protein chaperone that mediates the interactions between different proteins inside the spliceosome.

ACO1 has a part in an iron sensor. ACO1 catalyzes the stereo-specific isomerization of citrate to isocitrate via cis-aconitate in the tricarboxylic acid cycle, a non-redox-active process.

Protein tyrosine phosphatase mitochondrial 1 (PTPMT1) is a broadly expressed PTP membrane protein with high expression levels in pancreatic beta cells. The PTPMT1 protein is completely restricted to the matrix face of the inner membrane of the mitochondrion. PTPMT1 is responsible for dephosphorylating mitochondrial proteins and thus has a major role in the production of ATP. PTPMT1 exhibits a specific preference for the lipid signaling molecule phosphatidylinositol 5-phosphate as substrate.

TATDN3 is a member of the great superfamily of metalloenzymes. TATDN3 binds 2 divalent metal cations per subunit.

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.

Methionyl Aminopeptidase 1D (METAP1D) is a part of the peptidase M24A family. METAP1D which is overexpressed in colon cancer cell lines participates in tumorigenesis. METAP1D eliminates methionine from the N-terminus of nascent proteins.

Adenylate kinases play a role in regulating the adenine nucleotide composition within a cell by catalyzing the reversible transfer of phosphate groups among adenine nucleotides. There are 3 types of adenylate kinase isozymes, AK1, AK2, and AK3 in vertebrates. Expression of these isozymes are tissue-specific and developmentally regulated. AK2 is localized in the mitochondrial intermembrane space and is involved in apoptosis. AK2 is mutated in individuals with reticular dysgenesis.

Pyroglutamyl-Peptidase I (PGPEP1) is an omega peptidase which detaches pyroglutamyl residues from the amino termini of peptides and proteins. PGPEP1 is a cytosolic cysteine peptidase which is expressed in most cell types. PGPEP1 enzyme has need of s a thiol-reducing agent for activity. PGPEP1 is possibly involved in the inactivation of biologically active peptides which have an amino terminal pyroglutamyl group, for instance peptides as neurotensin, luteinizing hormone releasing hormone, and thyrotropinreleasing hormone.

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.

Staphylokinase (SAK) is a 136-amino acidenzymefrom Staphylococcus aureus. It is positively regulated by the "agr" gene regulator. It activates plasminogen, which in turn can degrade various host proteins during infection.

Ectonucleotide Pyrophosphatase-2, aka ENPP2, a part of the ectonucleotide pyrophosphatasefamily. ENPP2 is able to cut the phosphodiester bond between the alpha and the beta position of triphosphate nucleotides, acting as an ectonucleotide phosphodiesterase producing pyrophosphate, as most members of the ENPP family. It is unlike ENPP-1 and ENPP-3, has weak activity against nucleotides, but shows a lysophospholipase D activity which allows the formation of LPA and choline from lysophosphatidylcholine. As well, ENPP-2 and LPA are involved in several inflammatory-driven diseases such as arthritis and asthma.

Carbohydrate Sulfotransferase 5 (CHST5) is a Golgi-embedded enzyme that is found in B cells, T cells and intestinal epithelium and is also mediates sulfation of keratan in cornea. CHST5 is a sulfotransferase that utilizes 3'-phospho-5'-adenylyl sulfate (PAPS) as sulfonate donor to catalyze the transfer of sulfate to position 6 of non-reducing N-acetylglucosamine residues of keratan. CHST5 works on the non-reducing terminal GlcNAc of short andlong carbohydrate substrates that have poly-N-acetyllactosamine structures.

Arginase-1 is part of the urea cycle, it catalyzes the hydrolysis of arginine to ornithine and urea. There are two isoforms of mammalian arginase which differ in their tissue location, subcellular localization, immunologic crossreactivity & physiologic role. Arginase-1is a cytosolic enzyme and expressed primarily in the liver tissue. Inherited deficiency in this enzyme may lead toargininemia, which is an autosomal recessive disease in which hyperammonemia is detected.

PCMT1 enzyme catalyses the methyl esterification of L-isoaspartyl and D-aspartyl residues in peptides and proteins that result from spontaneous decomposition of normal L-aspartyl and L-asparaginyl residues. PCMT1 is involved in the repair and/or degradation of damaged proteins.