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HECT and RLD Domain Containing E3 Ubiquitin Protein Ligase 5 (HERC5) is a member of the HERC family of ubiquitin ligases, found in a cluster of HERC family genes on chromosome 4. HERC5 is a protein with a HECT domain and 5 RCC1 repeats. The HERC5 protein localizes to the cytoplasm and perinuclear region and serves as an INF-induced E3 protein ligase that mediates ISGylation of protein targets. HERC5 exhibits antiviral activity towards HIV-1, influenza A virus and human papillomavirus. HERC5 is a major E3 ligase for ISG15 conjugation. HERC5 also serves as a positive regulator of innate antiviral response in cells induced by INF. Pro-inflammatory cytokines upregulate HERC5 in endothelial cells. HERC5 is physically connected with polyribosomes, broadly modifies recently synthesized proteins in a cotranslational fashion.

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.

PCNA is located in the nucleus and is a cofactor of DNA polymerase delta. PCNA acts as a homotrimer and helps elevate the processivity of leading strand synthesis during DNA replication. In reaction to DNA damage, PCNA is ubiquitinated and takes part in the RAD6-dependent DNA repair pathway. 2 transcript variants encoding the same protein have been found for PCNA gene. Pseudogenes of this PCNA gene have been described on chromosome 4 and on the X chromosome. PCNA is expressed during late G1- phase, S-phase of mitosis and persists until the end of the M-phase because of its long biological half-life. PCNA is induced by UV irradiation.

Fructose-1,6-bisphosphatase isozyme 2 (FBP2) is a part of the FBPase class 1 family. FBP2 is a gluconeogenesis regulatory enzyme Which catalyzes the hydrolysis of fructose 1,6-bisphosphate to fructose 6-phosphate and inorganic phosphate.

DNA polymerase beta (POLB) is a member of the DNA polymerase type-X family. In eukaryotic cells, POLB performs base excision repair necessary for DNA maintenance, replication, recombination, and drug resistance. POLB has 2 separate domains; the larger is the polymerase domain itself, whereas a small basic N-terminal domain contains an AP lyase activity which excises the abasic sugar-phosphate residue at the strand break. POLB fills single nucleotide gaps in DNA produced by the base excision repair pathway of mammalian cells. POLB overexpression, as seen in some human tumors, could convene an increase in spontaneous mutagenesis.

Thioredoxins are small disulphide-containing redox proteins (within the conserved Cys-Gly-Pro-Cys active site) that have been found in all the kingdoms of living organisms. Thioredoxin contains a single disulfide active site and serves as a general protein disulphide oxidoreductase. Thioredoxins are involved in the first unique step in DNA synthesis. It interacts with a broad range of proteins by a redox mechanism based on reversible oxidation of two cysteine thiol groups to a disulphide, accompanied by the transfer of two electrons and two protons. The net result is the covalent interconversion of a disulphide and a dithiol. It has been suggested that thioredoxin may catalyze the formation of correct disulfides during protein folding because of its ability to act as an efficient oxidoreductant. Trx also provides control over a number of transcription factors affecting cell proliferation and death through a mechanism referred to as redox regulation.

Phosphoribosyl Pyrophosphate Synthetase-Associated Protein 2 (PRPSAP2) is a protein which relates with the enzyme phosphoribosylpyrophosphate synthetase (PRS). PRS catalyzes the formation of phosphoribosylpyrophosphate which is a substrate for synthesis of purine, pyrimidine, histidine, tryptophan and NAD. PRS is a complex with 2 catalytic subunits and 2 associated subunits. PRPSAP2 encodes a non-catalytic associated subunit of PRS.

GOT1 is a pyridoxal phosphate-dependent enzyme which exists in cytoplasmic and mitochondrial forms, GOT1 and GOT2, which participate in amino acid metabolism and the urea and tricarboxylic acid cycles. Both enzymes are homodimeric and show close homology.

PSMG4 is a chaperone protein that enhances assembly of the 20S proteasome. PSMG4 cooperates with alpha and beta subunits of the 20S proteasome and with PSMG3 but disconnects when the POMP is recruited before the formation of half-proteasomes.

Prostaglandin Reductase 1 (PTGR1) is a member of the NADP-dependent oxidoreductase L4BD family. PTGR1 catalyzes the conversion of leukotriene B4 into its biologically less active metabolite, 12-oxo-leukotriene B4, thus being a primary step of metabolic inactivation of leukotriene B4. PTGR1 is highly expressed in the kidney, liver, and intestine but not in leukocytes.

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.

Carboxymethylenebutenolidase homolog (CMBL) is a cysteine hydrolase of the dienelactone hydrolase family which is highly expressed in the liver cytosol. CMBL is the human homolog of Pseudomonas dienelactone hydrolase, which is a protein that participates in the bacterial halocatechol degradation pathway. CMBL which preferentially cleaves cyclic esters activates medoxomil-ester prodrugs in which the medoxomil moiety is coupled with an oxygen atom. CMBL is inhibited by PCMB (p-chloromercuribenzoate) and is encoded by a gene which maps to human chromosome 5p15.2. CMBL can also activate beta-lactam antibiotics faropenem medoxomil and lenampicillin. CMBL is widely expressed, with the highest levels in the liver, followed by the kidney, small intestine and the colon.

CNDP Dipeptidase 2 (CNDP2), is a cytosolic, non-specific dipeptidase which is a part of the peptidase M20A protein family. CNDP2 is a secreted peptidase homologous to M20 peptidases. CNDP2 expresses through all adult and fetal tissue, though, an isoform missing exons 3 and 4 expresses in all fetal tissue in adult liver. Over expression of CPGL-B in hepatocellular carcinoma cells results in significant inhibition of HC cell viability, colony formation, cell invasiveness and tumor configuration.

QDPR belongs to the short-chain dehydrogenases/reductase (SDR) family of enzymes. Operating as a homodimer, QDPR has an imperative role in the recycling of tetrahydrobiopterin (BH4), a vital cofactor for the hydroxylation of the aromatic amino acids (tryptophan, tyrosine and phenylalanine). More precisely, QDPR catalyzes the regeneration of BH4 from quinonoid dihydrobiopterin (qBH2), the product generated from the hydroxylation reactions. Mutations in the QDPR gene may lead to phenylketonuria II.

Dehydrogenase/reductase SDR family member 9 (DHRS9) functions as a homotetramer, which converts both 3-alpha-tetrahydroprogesterone (allopregnanolone) and 3-alpha-androstanediol to dihydroxyprogesterone and is believed to have a part in retinoic acid biosynthesis.

Borrelia is a part of the genus of bacteria of the spirochete phylum. Borrelia causes borreliosis, which is a zoonotic, vector-borne disease transmitted mostly by ticks and some by lice, depending on the species. Of the 36 known species of Borrelia, 12 are distinguished to cause Lyme disease or borreliosis and are transmitted by ticks. The Gram-negative bacterium Borreliella spielmanii is one of the pathogens of the Borreliella burgdorferi sensu lato complex causing Lyme disease. DbpA, also known as p17 or Osp17, is a heterogeneous protein among the human pathogenic B. burgdorferi sensu lato species.

PAX9 (Paired box protein Pax-9) belongs to the paired box (PAX) family of transcription factors. Members of PAX9 family typically contain a paired box domain, an octapeptide, and a paired-type homeodomain. These genes play critical roles during fetal development and cancer growth. In addition, PAX9 is vital for the development of different organs and skeletal elements.

FABP1 (Fatty acid binding protein1) encodes the fatty acid binding protein found in liver. FABP1 is composed of ten antiparallel beta strands that form a barrel with a bigger binding pocket than the other FABPs allowing it to accommodate two fatty acid. This protein binds free fatty acids and their coenzyme A derivatives, bilirubin, and some other small molecules in the cytoplasm; it may be involved in intracellular lipid transport and metabolism.

Peptidase Inhibitor 3, also referred to PI3, is neutrophil and pancreatic elastase-specific inhibitor of skin. The protein may prevent elastase mediated tissue proteolysis. PI3 has shown inhibition of alpha-4-beta-2/CHRNA2-CHRNB2 nicotinic acetylcholine receptor, a weak inhibition on Kv11.1/KCNH2/ERG1 and on the transient receptor potential cation channel subfamily V member 1.

G3BP1 belongs to the heterogeneous nuclear RNA-binding proteins and is also an element of the Ras signal transduction pathway. G3BP1 is one of the DNA-unwinding enzymes that favors partially unwound 3'-tailed substrates and is also able to unwind partial RNA/DNA and RNA/RNA duplexes in an ATP-dependent fashion. G3BP1 binds specifically to the Ras-GTPase-activating protein by associating with its SH3 domain. In addition, G3BP1 cleaves exclusively between cytosine and adenine and cleaves MYC mRNA preferentially at the 3'-UTR.

PSMB6 belongs to the proteasome B-type family (T1B family) which is a 20S core beta subunit in the proteasome. The PSMB6 is not present in the immunoproteasome and is replaced by PSMB9. The proteasome is a multicatalytic proteinase complex with an extremely ordered ring-shaped 20S core structure. The core structure is comprised of 4 rings of 28 non-identical subunits; 2 rings are composed of 7 alpha subunits and 2 rings are composed of 7 beta subunits.

Cysteine-Rich Secretory Protein 2 (CRISP2) regulates some ion channels activity and thereby regulates calcium fluxes during sperm capacitation. Amongst its related pathways are p53 signaling. Diseases related with CRISP2 include epididymitis and orchitis.

Cystathionine gamma-lyase or cystathionase (CTH) is a member of the trans-sulfuration enzymes family. CTH is an enzyme which breaks down cystathionine into cysteine and alpha-ketobutyrate. The CTH catalyzes the last step in the transsulfuration pathway from methionine to cysteine. Glutathione synthesis in the liver is dependent upon the availability of cysteine. Mutations in the CTH gene cause cystathioninuria.

Erythrocyte acylphosphatase (ACYP1) is a cytosolic enzyme which catalyzes the hydrolysis of the carboxyl-phosphate bond of acylphosphates. There are two acylphophatase isoenzymes: ACYP1 and ACYP2. These isoenzymes share 60% homology and have the same substrate specificity, even though ACYP1 has a higher catalytic activity than ACYP2.