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DNA Cytosine-5--Methyltransferase 3-Like (DNMT3L) is a nuclear protein with similarity to DNA methyltransferases, but is not believed to act as a DNA methyltransferase since it doesn’t contain the amino acid residues needed for methyltransferase activity. Nevertheless, DNMT3L stimulates de novo methylation by DNA cytosine methyltransferase 3 alpha and is assumed to be required for the formation of maternal genomic imprints. DNMT3L also mediates transcriptional repression as a result of interaction with histone deacetylase 1. DNMT3L is a catalytically inactive regulatory factor of DNA methyltransferases, which is vital for the function of DNMT3A and DNMT3B. DNMT3L activates DNMT3A and DNMT3B by binding to their catalytic domain. Furthermore, DNMT3L accelerates the binding of DNA and AdoMet to the methyltransferases and dissociates from the complex after DNA binding to the methyltransferases.

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.

Mitochondrial methylglutaconyl-CoA hydratase (AUH) is involved in the amino acid degradation pathway by catalyzing the conversion of 3-methylglutaconyl-CoA to 3-hydroxy-3-methylglutaryl-CoA and water. AUH Human is expressed as a single mRNA species of 1.8 kb, and translated as a 40kDa precursor protein which is consequently processed to a 32kDa mature form. AUH has a very low enoyl-CoA hydratase activity. The AUH protein binds to the AU-rich element (ARE), which is a common element found in the 3' UTR of rapidly decaying mRNA such as c-fos, c-myc and granulocyte/ macrophage colony stimulating factor. AU-rich elements are involved in directing RNA to rapid degradation and deadenylation. In addition, AUH is homologous to enol-CoA hydratase, which is an enzyme involved in fatty acid degradation, and has been shown to have intrinsic hydratase enzymatic activity. AUH is therefore a bifunctional chimera between RNA binding and metabolic enzyme activity.

UFC1 is a member of the ubiquitin-conjugating enzyme family. UFC1 is an E2-like conjugating enzyme for ubiquitin-fold modifier-1. UFM1 is activated by UBA5 (a novel E1-like enzyme) by forming a high-energy thioester bond. Activated UFM1 is subsequently transferred to its cognate E2-like enzyme, UFC1, in a similar thioester linkage.

Inorganic pyrophosphatase (ppa) is a member of the Ppase family. PPA is an enzyme which catalyzes the conversion of one molecule of pyrophosphate to two phosphate ions. Since this is a highly exergonic reaction, it can therefore be coupled to unfavorable biochemical transformations in order to drive these transformations to completion. The role of the PPA enzyme is a critical one in the lipid metabolism (including lipid synthesis and degradation), calcium absorption and bone formation, DNA synthesis, as well as other biochemical transformations.

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.

Uracil DNA glycosylase (UDG), or uracil-DNA glycosylase 1, is a crucial enzyme found in all life forms, involved in repairing damaged DNA by specifically removing uracil bases that are misincorporated into DNA during replication or deaminated cytosine. In various organisms, UDG goes by different names, such as b2580, JW2564, EC 3.2.2.27, DGU, UNG15, HIGM5, EC 3.2.2, HIGM4, and UNG2. Here, we delve into the E. coli UDG, examining its structure, function, and applications in molecular biology.

Structure: The crystal structure of E. coli UDG has been extensively studied, revealing that it belongs to the uracil DNA glycosylase (UDG) superfamily. The E. coli UDG monomer has 229 amino acids with a molecular weight of 25 kDa. The protein has a beta-sheet-rich structure with an alpha-helix on one side and a groove on the other side that binds to DNA. The active site of E. coli UDG contains a conserved glutamic acid residue that acts as a catalytic base to facilitate the hydrolysis of the N-glycosidic bond between uracil and the sugar phosphate backbone.

Function: E. coli UDG plays a critical role in maintaining the integrity of the genome by preventing the accumulation of mutations that can arise from the incorporation of uracil into DNA. Uracil in DNA can occur spontaneously from the deamination of cytosine or can be incorporated during DNA synthesis when dUTP is used instead of dTTP. Unrepaired uracil bases can lead to DNA damage and genomic instability, possibly resulting in cell death or disease. E. coli UDG specifically recognizes and removes uracil bases from DNA, creating an abasic site that is further processed by other repair enzymes.

MGMT is an enzyme that repairs O-6-methylguanine, a mutagenic DNA base damaged by endogenous and environmental alkylating agents and takes part in the cellular defense against the biological effects of O-6-methylguanine in DNA. MGMT repairs alkylated guanine in DNA by stoichiometrically transferring the alkyl group at the O-6 position to a cysteine residue in the enzyme. abnormal MGMT expression correlates with the prognosis in human solid cancers. MGMT decrease of expression is correlated with methylation. The human MGMT is a negative regulator of estrogen receptor-mediated transcription upon alkylation DNA damage. MGMT promoter hypermethylation plays an important role in the early steps of colorectal carcinogenesis. Abnormal promoter hypermethylation of MGMT gene is associated with oral squamous cell carcinomas.

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.

GOT2 is a pyridoxal phosphate-dependent enzyme which is found in cytoplasmic and inner-membrane mitochondrial forms, GOT1 and GOT2. GOT2 is invloved in amino acid metabolism and the urea and tricarboxylic acid cycles. The 2 enzymes are homodimeric and demonstrate close homology.

ALDOB is a tetrameric glycolytic enzyme which catalyzes the reversible cleavage of fructose 1-phosphate into dihydroxyacetone phosphate and glyceraldehyde. Fructose-bisphosphate aldolase B (ALDOB) is one of 3 known aldolase isoenzymes, and is located in the kidney and the small adult intestine where it is linked with aldolases A or C. ALDOB is regulated by Insulin and glucagon and is implicated in hereditary fructose intolerance disease.

UBE2K belongs to the ubiquitin-conjugating enzymes family which take part in many cellular processes such as selective protein degradation, DNA repair, cell cycle control, and sporulation. In this mechanism, the ATP-coupled activation and subsequent ligation of ubiquitin are catalyzed by separate enzymes functionally linked by ubiquitin carrier protein UBC1. In addition, UBE2K is involved in Alzheimer's disease, Huntington's disease and antigen processing through its interaction with amyloid-?, huntingtin, and MHC-heavy chain proteins.

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.

GPD1 enzyme catalyzes the reduction of dihydroxyacetone phosphate to sn-glycerol 3-phosphate. (sn-glycerol 3-phosphate + NAD+ = glycerone phosphate + NADH) previous names for glycerol-3-phosphate dehydrogenase include alpha glycerol-3-phosphate dehydrogenase and glycerolphosphate dehydrogenase. However, GPD1 differs from glyceraldehyde 3-phosphate dehydrogenase (GAPDH) whose substrate is an aldehyde not an alcohol.

NEDD8-activating enzyme E1 catalytic subunit (UBA3) is the catalytic subunit of the dimeric UBA3-NAE1 E1 enzyme, which belongs to the E1 ubiquitin-activating enzyme family. E1 activates NEDD8 by initially adenylating its C-terminal glycine residue with ATP, afterwards linking this residue to the side chain of the catalytic cysteine, generating a NEDD8-UBA3 thioester and free AMP. E1 at last transfers NEDD8 to the catalytic cysteine of UBE2M. The UBA3 enzyme connects with AppBp1, an amyloid beta precursor protein binding protein, to form a heterodimer, and at that point the enzyme complex activates NEDD8, a ubiquitin-like protein, which controls cell division, signaling and embryogenesis.

Glutaminyl-Peptide Cyclotransferase, also known as QPCT is a member of the glutaminyl-peptide cyclotransferase family. QPCT is responsible for the biosynthesis of pyroglutamyl peptides. Furthermore, QPCT is partial against acidic and tryptophan residues adjacent to the N-terminal glutaminyl residue and a lack of importance of chain length following the second residue. QPCT catalyzes N-terminal pyroglutamate formation, also in vitro, it catalyzes pyroglutamate formation of N-terminally truncated form of APP amyloid-beta peptides [Glu-3]-beta-amyloid.

RDH12 is a member of the short-chain Dehydrogenases / Reductases (SDR) family. RDH12 is found generally in brain, stomach, eye, skeletal muscle and kidney. RDH12 is a NADPH-dependent retinal reductase whose main activity is toward 9-cis and all-trans-retinol. In addition, RDH12 takes part in the metabolism of short-chain aldehydes but does not display steroid dehydrogenase activity.

MTHFS is a cytosolic protein which takes part in the formate metabolic process. MTHFS along with a magnesium cofactor catalyzes the ATP-dependent reaction which reduces 5-formyltetrahydrofolate (5-MTHF) to 5,10-methenyltetrahydrofolate(MTHF). MTHF is the substrate used by MTHFR (methylenetetrahydrofolate reductase) to generate 5-MTHF. In addition, MTHF is a coenzyme used in thymidine biosynthesis by thymidylate synthase (FAD).

Alanine transaminase or ALT is a transaminaseenzyme.
ALT is found in serumand in various bodily tissues, but is most commonly associated with the liver; It catalyzes the transfer of an aminogroup from alanineto a-ketoglutarate, the products of this reversible transaminationreaction being pyruvateand glutamatealanine+ a-ketoglutarate= pyruvate+ glutamate
It is commonly measured clinically as a part of a diagnostic liver function test, to determine liver health. It is also called serum glutamate pyruvate transaminase (SGPT) or alanine aminotransferase (ALAT). Diagnostically, it is almost always measured in units/litre (U/L).

Chitodextrinase is a unique membrane-bound endoenzyme. The chitodextrinase enzyme cleaves soluble oligomers, but not chitin, to the di- and trisaccharides. Chitodextrinase is unable to solubilize chitin, but it can catalyze the hydrolysis of high to low molecular weight soluble chitin oligosaccharides.

GDA is a member of the ATZ/TRZ family and is in charge for the hydrolytic deamination of guanine. GDA takes part in microtubule assembly. Multiple transcript variants encoding different isoforms have been found for GDA.

LCAT is an extracellular cholesterol esterifying enzyme, lecithin-cholesterol acyltransferase. The esterification of cholesterol is required for cholesterol transport. LCAT is a essential enzyme in the extracellular metabolism of plasma lipoproteins.

PNMT is an enzyme located in the adrenal medulla and it catalyzes the final step of the catecholamine biosynthesis pathway. PNMT has beta-carboline 2N-methyltransferase activity. PNMT takes part in regulating epinephrine production. Glucocorticoid receptors form multimers of PNMT independent of the DNA binding domain. PNMT expression is regulated late in mouse gestation by AP2-alpha and glucocorticoids.