Transferase

SULT1B1 enzyme in humans is encoded by the SULT1B1 gene. SULT1B1 holds a binding site for 3-prime-phosphoadenosine 5-prime-phosphosulfate, a sulfate donor, in addition to a cysteine residue conserved in the ST1 gene family of sulfotransferases. Sulfotransferases like SULT1B1 catalyze the biotransformation of a great amount of endogenous amalgams such as bile acids, neurotransmitters, steroids, and thyroid hormones, in addition to drugs and xenobiotics.

Sulfotransferase 1A2 (SULT1A2) belongs to the sulfotransferase family. Sulfotransferase enzymes catalyze the sulfate conjugation of many hormones, neurotransmitters, drugs, and xenobiotic compounds. SULT1A2 mediates the metabolic activation of carcinogenic N-hydroxyarylamines to DNA binding products and might thus participate as a modulating factor of cancer risk.

OTC is a member of the ATCase/OTCase family. OTC has a key part in the urea cycle, catalyzing the second step in this pathway: the transformation of L-orthinine and carbamoyl phosphate to L-citrulline. In humans, the urea cycle is a vital pathway to detoxification of ammonia. Alterations in the gene encoding OTC are linked to the X-linked disorder OTCD (ornithine carbamoyltransferase deficiency). OTCD disorder of the urea cycle is characterized by hyperammonemia.

Ornithine Aminotransferase is a mitochondrial enzyme which is an important factor that converts arginine and ornithine into the major excitatory and inhibitory neurotransmitters glutamate and GABA. Ornithine Aminotransferase mutations result in a deficiency that cause the autosomal recessive eye disease Gyrate Atrophy.

Alpha-N-acetylgalactosaminide alpha-2,6-sialyltransferase 5 or ST6GALNAC5, is part of the glycosyltransferase 29 group of proteins. ST6GALNAC5 is a sialyltransferase that takes part in the synthesis of ganglioside GD1a. This protein is part of the protein glycosylation transduction, meaning, modification of proteins. ST6GALNAC5 is expressed strictly in the brain tissue, and is a crucial component in breast cancer cells metastasis to the brain tissue. It is thought to enable cancer cells to go through the blood-brain barrier.

Betaine-Homocysteine Methyltransferase 2 (BHMT2) is involved in the regulation of homocysteine metabolism. Homocysteine is a sulfur-containing amino acid which has a key role in methylation reactions. Transfer of the methyl group from betaine to homocysteine generates methionine, which donates the methyl group to methylate DNA, proteins, lipids, and other intracellular metabolites. BHMT2 is one of two methyl transferases which can catalyze the transfer of the methyl group from betaine to homocysteine. BHMT2 converts homocysteine to methionine using S-methylmethionine (SMM) as a methyl donor. Homocysteine metabolism anomalies are implicated in disorders varying from vascular disease to neural tube birth defects such as spina bifida.

ST6GAL1 also known as ST6 Beta-Galactosamide Alpha-2,6-Sialyltranferase 1, is part of the glycosyltransferase family 29. ST6GAL1 is a type II membrane protein which catalyzes the transfer of sialic acid from CMP-sialic acid to galactose-containing substrates. Furthermore, ST6GAL1 is normally found in the Golgi however it can be proteolytically processed to a soluble form, ST6GAL1 is also involved in the generation of the cell-surface carbohydrate determinants as well differentiation antigens HB-6, CD75, and CD76.

Betaine-homocysteine methyltransferase (BHMT) is a cytosolic enzyme that catalyzes the conversion of betaine and homocysteine to dimethylglycine and methionine, respectively. BHMT displays differential expression in a model of liver cirrhosis.

ST6GAL1 also known as ST6 Beta-Galactosamide Alpha-2,6-Sialyltranferase 1, is part of the glycosyltransferase family 29. ST6GAL1 is a type II membrane protein which catalyzes the transfer of sialic acid from CMP-sialic acid to galactose-containing substrates. Furthermore, ST6GAL1 is normally found in the Golgi however it can be proteolytically processed to a soluble form, ST6GAL1 is also involved in the generation of the cell-surface carbohydrate determinants as well differentiation antigens HB-6, CD75, and CD76.

ST3 Beta-Galactoside Alpha-2,3-Sialyltransferase 5, also know as ST3GAL5 belongs to the glycosyltransferase family 29 and localized to the Golgi apparatus. ST3GAL5 is known to play a part in the induction of cell differentiation, modulation of cell proliferation, maintenance of fibroblast morphology, signal transduction, and integrin-mediated cell adhesion. ST3GAL5 is a type II membrane protein which catalyzes the formation of GM3 with lactosylceramide as the substrate. Mutation in this ST3GAL5 has been connected with Amish infantile epilepsy syndrome. Transcript variants encoding various isoforms have been found for this gene.

EGF Domain-Specific O-Linked N-Acetylglucosamine Transferase (EOGT) takes part in the regulation of Notch receptor. EOGT catalyzes the transfer of a single N-acetylglucosamine from UDP-GlcNAc to a serine/ threonine residue in extracellular proteins resulting in their modification with a beta-linked N-acetylglucosamine (O-GlcNAc). EOGT mainly glycosylates the Thr residue positioned between the fifth and sixth conserved cysteines of folded EGF-like domains.

N-terminal Xaa-Pro-Lys N-methyltrasferase1, also known as NTMT1 belongs to the methyltransferase superfamily. NTMT1 catalyzesthe transfer of the methyl group from the S-adenosyl-l-methionine to the protein ?-amine, resulting in the formation of S-adenosyl-l-homocysteine and ?-N-methylated proteins. NTMT1 is a remarkable potential anticancer targetsince it is overexpressed in gastrointestinal cancers in addition to his essential function in cell mitosis.

Beta-1,3-N-Acetylglucosaminyltransferase 2 (B3GNT2) is a part of the beta-1,3-N-acetylglucosaminyltransferase family which takes part in the synthesis of poly-N-acetyllactosamine. B3GNT2 is a type II transmembrane protein which prefers the substrate of lacto-N-neotetraose. B3GNT2 catalyzes the initiation and elongation of poly-N-acetyllactosamine chains and comprises the main polylactosamine synthase.

Beta-1,3-glucuronyltransferase 3 (B3GAT3) is involved in forming the linkage tetrasaccharide present in heparan sulfate and chondroitin sulfate. B3GAT3 has a part in the biosynthesis of l2/HNK-1 carbohydrate epitope on glycoproteins. B3GAT3 shows strict specificity for Gal-beta-1,3-Gal-beta-1,4-Xyl, exhibiting negligible incorporation into other galactoside substrates including Galbeta1-3Gal beta1-O-benzyl, Galbeta1-4GlcNAc and Galbeta1-4Glc.

NNMT is part of the family of transferases, especially those transferring one-carbon group methyltransferases. NNMT is mostly expressed in the liver, and a lower expression is seen in the kidney, lung, skeletal muscle, placenta and heart. NNMT catalyzes the N-methylation of nicotinamide and other pyridines to form pyridinium ions. This activity is significant for biotransformation of many drugs and xenobiotic compounds. NNMT is accountable for the enzymatic activity which uses S-adenosyl methionine as the methyl donor. NNMT expression is related with tumor stage and DFS time in hepatocellular carcinoma cases. NNMT is a good candidate as a tumor marker of various kinds of cancers. NNMT serum levels have significance in the premature detection and in the management of patients with colorectal cancer.

NNMT is part of the family of transferases, especially those transferring one-carbon group methyltransferases. NNMT is mostly expressed in the liver, and a lower expression is seen in the kidney, lung, skeletal muscle, placenta and heart. NNMT catalyzes the N-methylation of nicotinamide and other pyridines to form pyridinium ions. This activity is significant for biotransformation of many drugs and xenobiotic compounds. NNMT is accountable for the enzymatic activity which uses S-adenosyl methionine as the methyl donor. NNMT expression is related with tumor stage and DFS time in hepatocellular carcinoma cases. NNMT is a good candidate as a tumor marker of various kinds of cancers. NNMT serum levels have significance in the premature detection and in the management of patients with colorectal cancer.

Glycylpeptide N-tetradecan-oyltransferases 2 (NMT2) is a cytoplasmic protein which is a member of the NMT family of proteins. The proteins in the NMT family catalyze the addition of a myristoyl group to the N-terminal glycine residue of eukaryotic, fungal and viral proteins. These proteins are mostly detected in the heart, gut, kidney, liver and placenta. NMT catalyzes the reaction of N-terminal myristoylation of various signaling proteins. NMT transfers myristic acid from myristoyl coenzyme A to the amino group of a protein's N-terminal glycine residue. There are several distinct NMTs which vary in the molecular weight and /or subcellular distribution.

Myristate, a rare 14-carbon saturated fatty acid, is co-translationally attached by an amide linkage to the N-terminal glycine residue of cellular & viral proteins with various functions. N-Myristoyltransferase 1, also known as NMT1 catalyzes the transfer of myristate from CoA to proteins. NMT1 seems to be irreversible and is essential for full expression of the biologic activities of several N-myristoylated proteins, as well as the alpha subunit of the signal-transducing guanine nucleotide-binding protein, G protein.

Nicotinamide Nucleotide Adenylyltransferase 2, also known as NMNAT2 is a member of the nicotinamide mononucleotide adenylyltransferase (NMNAT) enzyme family, members of which catalyze a vital step in NAD (NADP) biosynthetic pathway. Unlike the other human family member, which is localized to the nucleus, and is ubiquitously expressed; NMNAT2 is cytoplasmic, and is predominantly expressed in the brain. Two transcript variants encoding different isoforms have been found for NMNAT2. Among the diseases associated with NMNAT2 are tauopathy, and systemic lupus erythematosus.

NMNAT1 enzyme is vital for NAD biosynthesis, catalyzing the condensation of nicotinamide mononucleotide (NMN) or nicotinic acid mononucleotide (NaMN) with the AMP moiety of ATP to form NAD or NaAD. NMNAT1 is widely expressed with high levels in skeletal muscle, heart, liver and kidney. This protein appears to have the ability to protect against axonal degeneration following mechanical or toxic insults.

NMNAT1 enzyme is vital for NAD biosynthesis, catalyzing the condensation of nicotinamide mononucleotide (NMN) or nicotinic acid mononucleotide (NaMN) with the AMP moiety of ATP to form NAD or NaAD. NMNAT1 is widely expressed with high levels in skeletal muscle, heart, liver and kidney. This protein appears to have the ability to protect against axonal degeneration following mechanical or toxic insults.

NMNAT1 enzyme is vital for NAD biosynthesis, catalyzing the condensation of nicotinamide mononucleotide (NMN) or nicotinic acid mononucleotide (NaMN) with the AMP moiety of ATP to form NAD or NaAD. NMNAT1 is widely expressed with high levels in skeletal muscle, heart, liver and kidney. This protein appears to have the ability to protect against axonal degeneration following mechanical or toxic insults.

ASMT is a member of the methyltransferase superfamily. ASMT participates in melatonin biosynthesis. ASMT Expressed in brain, retina and pineal gland, ASMT utilities to catalyze the final reaction in the synthesis of melatonin, particularly the conversion of S-adenosyl-L-methionine and N-acetylserotonin to S-adenosyl-Lhomocysteine and melatonin.

Arsenic Methyltransferase (AS3MT) catalyzes the transfer of a methyl group from S-adenosyl-L-methionine (AdoMet) to trivalent arsenical and may have a role in arsenic metabolism. AS3MT methylates arsenite to produce methylarsonate, Me-AsO3H2, which is reduced by methylarsonate reductase to methylarsonite, Me-As(OH)2. Methylarsonite which is also a substrate, is transformed into the much less toxic complex dimethylarsinate (cacodylate), Me2As(O)-OH.

Ecto-ADP-Ribosyltransferase 4 or ART4 is typed as a glycosylphosphatidylinositol (GPI)-linked membrane protein which carries Dombrock blood group antigens. The development of this protein takes place at the highest levels in the fetal liver. the process of the ART4 development is regulated while the erythroid differentiation process occurs. ART4 is a is part of the Ribosyltransferase family.

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.

SHMT1 is a member of the SHMT family. SHMT1 is the cellular form of serine hydroxymethyltransferase, a pyridoxal phosphate-containing enzyme which catalyzes the reversible conversion of serine and tetrahydrofolate to glycine and 5 10-methylene tetrahydrofolate. In addition, SHMT1 specifically provides one-carbon units for thymidylate biosynthesis, reduces methylenetetrahydrofolate pools for S-adenosylmethionine (SAM) synthesis by synthesizing serine, sequesters 5-methyltetrahydrofolate and inhibits SAM synthesis.

APRT is part of the purine/pyrimidine phosphoribosyltransferase family. APRT enzyme catalyzes the formation of AMP and inorganic pyrophosphate from adenine and 5-phosphoribosyl-1-pyrophosphate (PRPP). APRT produces adenine as a by-product of the polyamine biosynthesis pathway. A homozygous deficiency in APRT causes 2,8-dihydroxyadenine urolithiasis. APRT catalyzes a salvage reaction resulting in the formation of AMP.

DLST catalyzes the general transformation of 2-oxoglutarate to succinyl-CoA and CO(2). DLST holds multiple copies of 3 enzymatic components: 2-oxoglutarate dehydrogenase (E1), dihydrolipoamide succinyltransferase (E2) and lipoamide dehydrogenase (E3).

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.

NAT6 is an enzyme that catalyzes the transfer of acetyl groups from acetyl-CoA to acrylamines. NAT6 is located mainly in the cytoplasm and its activity has been recognized by its feasibility to acetylate the N-terminus of proteins using a ping-pong-like mechanism and by its substrate specificity. Given that the NAT6 gene maps to the chromosomal region 3p21.3, which includes at least one tumor suppressor gene, the function of NAT6 plays an important role in cancer.

NAT1 is a member of the arylamine N-acetyltransferase family. NAT1 catalyzes N- or O-acetylation of heterocyclic and arylamine substrates in the detoxification of a large number of drugs. Several alleles triggering high levels of N-acetyltransferase activity were linked to colon and urinary bladder cancers, since NAT1 also bioactivate numerous known carcinogens. NAT1 aids metabolize drugs and other xenobiotics, and takes part in the detoxification of a plethora of hydrazine and arylamine drugs.

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.

Set 7/9 is a histone methyltransferase (HMTase) that transfers methyl groups to Lys4 of histone H3, in complex with S-adenosyl-L-methionine (AdoMet). The methylation of lysine residues of histones plays a critical role in the regulation of chromatin structure and gene expression.
Acetylation, phosphorylation and methylation of the amino-terminal tails of histone are thought to be involved in the regulation of chromatin structure and function. The enzymes identified in the methylation of specific lysine residue on histones belong to the SET family with just one exception. Set7/9, unlike most other SET proteins, is exclusively a mono-methylase.

Heparan Sulfate 3-O-Sulfotransferase 1 (HS3ST1), is sulfotransferase which uses 3'-phospho-5'-adenylyl sulfate (PAPS) to catalyze the transfer of a sulfo group to position 3 of glucosamine residues in heparan. HS3ST1 catalyzes the rate limiting step in the biosynthesis of heparan sulfate (HSact). This modification is a vital part in the biosynthesis of anticoagulant heparan sulfate since it concludes the structure of the antithrombin pentasaccharide binding site.

HPRT1 has a main part in the generation of purine nucleotides through the purine salvage pathway. HPRT1 primarily functions to salvage purines from degraded DNA to renewed purine synthesis. Therefore, it performs as a catalyst in the reaction between guanine and phosphoribosyl pyrophosphate to form GMP.

HPRT1 has a main part in the generation of purine nucleotides through the purine salvage pathway. HPRT1 primarily functions to salvage purines from degraded DNA to renewed purine synthesis. Therefore, it performs as a catalyst in the reaction between guanine and phosphoribosyl pyrophosphate to form GMP.

N-alpha-acetyltransferase 50 (NAA50) consists of 169 amino acid cytoplasmic protein belonging to the acetyltransferase family and GNAT subfamily. NAA50 is a likely catalytic component of the ARD1A-NARG1 complex which displays alpha acetyltransferase activity. NAA50 has also been shown to interact with MAK10 and is encoded by a gene that maps to human chromosome 3q13.2.

N-alpha-acetyltransferase 30 (NAA30) is catalytic subunit of the N-terminal acetyltransferase C (NatC) complex. NAA30 catalyzes acetylation of the N-terminal methionine residues of peptides beginning with Met-Leu-Ala and Met-Leu-Gly. In addition, NAA30 is essential for the lysosomal localization and function of ARL8B. The disease Eastern equine encephalitis has been associated with NAA30.

NAA10 is a member of the acetyltransferase family. NAA10 interacts with NAA15, HIF-1 and with the ribosome. In its binding to HIF-1, NAA10 functions as a protein acetyltransferase by regulating its stability. In various cell lines, NAA10 is downregulated in response to hypoxia. NAA10 is expressed during the course of the development of the brain.

N-6 Adenine-Specific DNA Methyltransferase 1, also known as N6AMT1 is part of the methyltransferase family. N6AMT1 is implicated in the methylation of release factor I during translation termination. In addition, N6AMT1 is involved in converting the arsenic metabolite monomethylarsonous acid to the less toxic dimethylarsonic acid.

Histamine N-Methyltransferase or HNMT, is located in the cell cytosol. Sadenosyl-L-methionine acts as a methyl donor for HNMT which inactivates histamine. By inactivation of histamine, it affects the immune system’s response. HNMT acts on histamine in body tissues such as kidney, central nervous system and bronchus. The protein has a crucial part in the airway response to histamine & histamine degradation process and regulation.

HNMT is located in the cytosol and uses S-adenosyl-L-methionine as the methyl donor. In the mammal’s brain,N(tau)-methylation controls the neurotransmitter activity of histamine since diamine oxidase is not located in the central nervous system. A well known genetic polymorphism influences the activity levels of HNMT gene product in red blood cells. HNMT inactivates histamine by n-methylation. HNMT is involved in degrading histamine and in regulating the airway response to histamine. Histamine is involved in regulation and modulation of immune response through the stimulation of four distinct subtypes of receptors, H1, H2, H3, and H4, that present on the target cells. Histamine is inactivated by the histamine-metabolizing enzyme HNMT in bronchus, kidney, and the central nervous system.

Aminomethyltransferase, mitochondrial isoform 1 (AMT) is a component of the glycine cleavage system termed T-protein. AMT reversibly catalyzes the degradation of the aminomethyl moiety of glycine attached to the lipoate cofactor of H-protein, leading to the production of ammonia, 5,10-methylenetetrahydrofolate, and dihydrolipoate-bearing H-protein in the presence of tetrahydrofolate.

Mercaptopyruvate Sulfurtransferase (MPST) catalyzes the transfer of a sulfur ion from 3-mercaptopyruvate to cyanide or other thiol compounds. MPST might be involved in cysteine degradation and cyanide detoxification. The MPST enzyme is regulated by oxidative stress and thioredoxin. In oxidative stress conditions, the catalytic cysteine site is transformed to a sulfenate which inhibits the MPST enzyme activity. The reduced thioredoxin cleaves an intersubunit disulfide bond to activate the redox switch and reactivate the enzyme. A deficiency in MPST activity is implicated in a rare inheritable condition known as MCDU (mercaptolactate-cysteine disulfiduria).

Spermidine/Spermine N1-Acetyltransferase 2, also known as SAT2 catalyzes the acetylation of polyamines (Acetyl-CoA + an alkane-alpha,omega-diamine = CoA + an N-acetyldiamine).

SAT-1 is a member the acetyltransferase family, and is a rate-limiting enzyme in the catabolic pathway of polyamine metabolism. SAT1 catalyzes the acetylation of spermidine and spermine, and is involved in the regulation of the intracellular concentration of polyamines and their transport out of cells. Therefore, SAT-1’s role is essential in polyamine homoeostasis, given that acetylated products are either excreted from the cell or oxidized by acetylpolyamine oxidase. Increased SAT1 activity causes variety of other effects which include pancreatic cells death, obstruction of regenerative tissue growth, behavioral changes, keratosis follicularis spinulosa decalvans (KFSD), and hair loss.
Defects in the SAT1 gene are linked to KFSD (keratosis follicularis spinulosa decalvans), which is a rare X-linked disorder affecting the skin and the eye. The KFSD affected men show thickening of the skin of the neck, ears, and extremities, particularly the palms and soles, loss of eyebrows, eyelashes and beard, thickening of the eyelids with blepharitis and ectropion, and corneal degeneration. Even though the majority of the affected families are compatible with an X-linked inheritance, KFSD are found to be clinically and genetically heterogeneous.

MMAB protein catalyzes the last step in the conversion of vitamin B(12) into adenosylcobalamin (AdoCbl), a vitamin B12 containing coenzyme for methylmalonyl-CoA mutase(MCM). Decreased MMAB activity leads to the inherited disorder vitamin B12 dependent methylmalonic aciduria linked to the cblB complementation group.

ACAT2 enzyme participates in lipid metabolism. ACAT2 takes part in lipoprotein assembly, catalyzing cholesterol esterification in mammalian cells. ACAT2 is an integral membrane protein that localizes to the endoplasmic reticulum of human intestinal cells. ACAT2 deficiency contributes to severe mental retardation and hypotonus.

Acetoacetyl-CoA thiolase (ACAT1) is an enzyme member of the membrane-bound acyltransferase family and Sterol o-acyltransferase subfamily. The ACAT1 enzyme catalyzes the reversible formation of acetoacetyl-CoA from 2 molecules of acetyl-CoA. ACAT1 plays a part in lipoprotein compilation and dietary cholesterol absorption. Added to its acyltransferase activity, ACAT1 acts as a ligase.