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Serine/Threonine-protein phosphatase PP1-alpha catalytic subunit (PPP1CA) is crucial for cell division, and participates in the regulation of glycogen metabolism, muscle contractility and protein synthesis. The PPP1CA protein may have a significant role in dephosphorylating substrates such as the postsynaptic density-associated Ca2+/calmodulin dependent protein kinase II.

PLA2G7 is a secreted enzyme which catalyzes the degradation of platelet-activating factor to biologically inactive products. The PLA2G7 enzyme is produced by inflammatory cells and hydrolyzes oxidised phospholipids in LDL. In the blood, PLA2G7 goes mainly with LDL and less than 20% is coupled with HDL.
PLA2G7 is implicated in the development of atherosclerosis and is also a marker for cardiac disease. PLA2G7 might have a major physiologic effect in the presence of inflammatory bodily responses.
PLA2G7 alters the action of PAF (platelet-activating factor) by hydrolyzing the sn-2 ester bond to yield the biologically inactive lyso-PAF. PLA2G7 has specificity for substrates with a short residue at the sn-2 position. PLA2G7 is inactive against long-chain phospholipids.
PLA2G7 gene defects are the source of platelet-activating factor acetylhydrolase deficiency, which is a trait that is present in 27% of the Japanese population.

Galactose-1-Phosphate Uridylyltransferase (GALT) catalyzes the 2nd step of the “Leloir pathway” of galactose metabolism, specifically the conversion of UDP-glucose + galactose-1-phosphate to glucose-1-phosphate + UDP-galactose. The deficiency of the GALT enzyme results in typical galactosemia in humans and may be fatal in the newborn stage if lactose is not eliminated from the diet. Galactosemia pathophysiology has not been clearly defined.

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.

PHPT1 is a member of the Janus protein familyand is 125 amino acid long. PHPT1 appears as a monomer in the cytoplasm and is an EDTA-insensitive phosphohistidine phosphatase. Overexpression of PHPT1 resolts in specific phosphohistidine phosphatase activity towards phosphopeptide I, with no activity detected towards phosphotyrosine, phosphothreonine and phosphoserine peptides.

FBP1 is a gluconeogenesis regulatory protein which catalyzes the hydrolysis of fructose 1,6-bisphosphate to fructose 6-phosphate and inorganic phosphate. FBP1 deficiency is associated with hypoglycemia and metabolic acidosis. FBP1 regulates mouse endogenous glucose production. FBP1 coupled with phosphofructokinase (PFK) takes part in the metabolism of pancreatic islet cells.

Ribophorin 2 (RPN2) is a dolichyl-diphosphooligosaccharide protein glycosyltransferase subunit 2. The Ribophorin 2 protein is part of an N-oligosaccharyl transferase complex which links high mannose oligosaccharides to asparagine residues found in the Asn-X-Ser/Thr consensus motif of nascent polypeptide chains. RPN2 is analogous in sequence to the yeast oligosaccharyl transferase subunit SWP1.

Dual specificity phosphatase 18 (DUSP18) belongs to the dual-specificity phosphatase (DSP) family, which catalyzes dephosphorylation of phosphotyrosine and phosphothreonine residues. DUSP18 has a preferential enzymatic activity for phosphorylated tyrosine residues over threonine residues, in addition DUSP18 dephosphorylates p-nitrophenyl phosphate (pNPP) in vitro. Furthermore, DUSP18 is inhibited by iodoarectic acid and is activated by manganese ions. DUSP18 is extensively expressed with the highest levels in the liver, brain, ovary and testis.

MUTM is a base excision repair enzyme that identifies and eliminates a large variety of oxidized purines from correspondingly impaired DNA. MUTM is nondismissable and essential to remove quickly its substrate lesions on the chromosome. MUTM, additionally, mends a large number of the lesions recognized by Endo III, signifying that MUTM takes a prominent part in the overall repair of both purine damage and pyrimidine damage in vivo.

AHCY is an enzyme that catalyzes the reversible hydrolysis of S-adenosylhomocysteine (AdoHcy) to adenosine (Ado) and L-homocysteine (Hcy). AHCY controls the intracellular S-adenosylhomocysteine (SAH) concentration that is crucial for transmethylation reactions. AHCY deficiency causes hypermethioninemia.

PPP3R2 is a calcium-dependent, calmodulin stimulated serine/threonine protein phosphatase. In eukaryotes, the phosphorylation and dephosphorylation of proteins on serine and threonine residues is a crucial means of regulating a wide range of cellular functions including division, homeostasis and apoptosis. Ordinarily the protein phosphatase (PP) holoenzyme is a trimeric complex composed of a regulatory subunit, a variable subunit and a catalytic subunit.

ENO1 is a homodimeric soluble protein that encodes a smaller monomeric structural lens protein, tau-crystallin. ENO1 is a glycolytic enzyme expressed in mainly all tissues. ENO1 isoenzyme full length protein is found in the cytoplasm. The shorter protein is formed from another translation start that is restricted to the nucleus, and binds to a component in the c-myc promoter. ENO1 is involved in anaerobic metabolism under hypoxic conditions and plays a role as a cell surface plasminogen receptor during tissue invasion. Irregular expression of Enolase-1 is linked with tumor progression in several cases of breast and lung cancer. Enolase-1 is as an auto antigen associated with Hashimoto's encephalopathy and severe asthma. ENO1 is the target protein of serum anti-endothelial antibody in Behcet's disease.

Protein Phosphatase 1D (PPM1D) belongs to the PP2C family of Ser/Thr protein phosphatases whose members are negative regulators of cell stress response pathways. PPM1D is induced by tumor suppressor protein TP53/p53 in response to multiple environmental stresses. PPM1D is a negative regulator of the activity of p38 MAP kinase through which it reduces the phosphorylation of p53 and suppresses p53-mediated transcription and apoptosis. PPM1D is located in a chromosomal area which enlarges in breast cancer.

Protein Phosphatase 1, Regulatory Subunit 8 (PPP1R8) is the RNA-binding subunit of a key species of protein phosphatase-1 in the nucleus. The PPP1R8 enzyme is an inhibitor subunit of the main nuclear protein phosphatase-1 (PP-1). PPP1R8 has RNA-binding activity however it doesn’t cleave RNA and may target PP-1 to RNA-associated substrates. Two isoforms of the PPP1R8 protein are specific inhibitors of type 1 serine/threonine protein phosphatases which can bind but not cleave RNA. The third isoform of the PPP1R8 protein is deficient in of the phosphatase inhibitory activity nonetheless it is a single-strand endoribonuclease comparable to RNase E of E. coli.

Protein Phosphatase 1, Regulatory Subunit 2 (PPP1R2) is an inhibitor of protein-phosphatase 1 which forms heterodimer with PP1. PPP1R2 is a part of the protein phosphatase inhibitor 2 family.

The protein kinase A holoenzyme is a heterotetramer composed of two types of subunits: Catalytic and Regulatory. The Catalyticsubunit contains the enzyme's active site. It also contains a domain that binds ATP and a domain that binds the regulatory subunit. The Regulatory subunit consists oftwo molecules which bind one another in an anti-parallel orientation to form a homodimer; for type I subunits- this binding is covalent via disulfide bonds. This subunit also has has two domains that bind cyclic AMP, a domain that interacts with a catalytic subunit, and an "auto-inhibitory" domain that serves as a substrate or pseudosubstrate for the catalytic subunit. Regulatory subunits may also have biologic activity distinct from their role in modulating catalytic subunit activity. Regulatory subunits exist in two major forms, RI and RII, with each form having two subtypes designated alpha and beta. Each of the four isotypes of the regulatory subunit is encoded by a different gene. In addition, three isotypes of the catalytic subunit have been identified (alpha, beta and gamma). The different isotypes tend to have different distributions within cells and among tissues. Type I enzymes inhabit cytoplasmic, soluble fractions of the cell, whereas type II enzymes tend to associate with cellular membranes.

Protein Phosphatase 2, Regulatory Subunit A Alpha, also known as PPP2R1A is part of the PPP family of phosphatases, which regulates a diversity of vital cellular processes. PPP2R1A subunit, PR65, functions as a scaffolding molecule which coordinates the assembly of the catalytic subunit and a variable regulatory B subunit. PPP2R1A is essential for proper chromosome segregation as well as for centromeric localization of SGOL1 in mitosis. Furthermore, PPP2R1A phosphorylation is an in vivo mechanism which regulates the PP2A signaling complex as well as increasing the PP2A activity in heart failure.

Acid phosphatase, prostate (ACPP) is a non-specific tyrosine phosphatase, which dephosphorylates a varied number of substrates under acidic conditions (pH 4-6) including alkyl, aryl, and acyl orthophosphate monoesters and phosphorylated proteins. ACPP has lipid phosphatase activity and inactivates lysophosphatidic acid in seminal plasma.

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.

GPI or Glucose-6-phosphate isomerase, is a protein, part of the multifunctional phosphoglucose isomerase family, which its members take part in energy pathways. GPI is a dimeric enzyme that enhances the isomerization of glucose-6-phosphate and fructose-6- phosphate (both reversible). In mammals, GPI acts as an angiogenic factor & tumor-secreted cytokine. The enzyme also acts as a neurotrophic factor for spinal & sensory neurons.

Group IB secretory phospholipase A2 (sPLA2-IB) mediates cell proliferation, cell migration, hormone release and eicosanoid production via its receptor in peripheral tissues. In the CNS, high-affinity binding sites of sPLA2-IB have been documented. sPLA2-IB induced neuronal cell death in a concentrationdependent manner depending on PGD2 metabolites, especially Delta12-PGJ2 that might mediate sPLA2-IB-induced apoptosis. The secretory PLA2 (sPLA2) family, in which 10 isozymes have been identified, consists of lowmolecular weight, Ca2+-requiring secretory enzymes that have been implicated in a number of biological processes, such as modification of eicosanoid generation, inflammation, and host defense.