Branched chain aminotransferase

branched chain aminotransferase
"RCSB Protein Data Bank - Structure Summary for 3DTF - Structural analysis of mycobacterial branched chain aminotransferase- implications for inhibitor design".
Identifiers
Symbol	BCAT
Alt. symbols	BCT
Entrez	587
HUGO	977
OMIM	113530
RefSeq	NM_001190
UniProt	O15382
Other data
EC number	2.6.1.42
Locus	Chr. 19 q13

Branched chain aminotransferase is an aminotransferase enzyme which acts upon branched-chain amino acids. It uses largely α-ketoglutarate in forming branched chain α-keto acids and glutamate.

The structure to the right of branched chain aminotransferase was found using X-ray diffraction with a resolution of 2.20 Å. The branched chain aminotransferase found in this image was isolated from mycobacteria. This protein is made up of two identical polypeptide chains. The protein is a total of 372 residues(1). As can be seen in the image, the protein is made of helices and beta sheets.

The biological function of branched chain aminotransferases (BCAT) is to catalyse the synthesis or degradation of the branched chain amino acids leucine, isoleucine, and valine(2). In humans, branched chain amino acids are essential and are degraded by BCATs.

(1) "RCSB Protein Data Bank - Structure Summary for 3DTF - Structural analysis of mycobacterial branched chain aminotransferase- implications for inhibitor design".

(2) "Structure and function of branched chain aminotransferases.". Prog Nucleic Acid Res Mol Biol 70: 175–206. 2001. doi:10.1016/s0079-6603(01)70017-7. PMID 11642362.

External links

branched-chain-amino-acid transaminase at the US National Library of Medicine Medical Subject Headings (MeSH)
"RCSB Protein Data Bank - Structure Summary for 3DTF - Structural analysis of mycobacterial branched chain aminotransferase- implications for inhibitor design".

Metabolism: Protein metabolism, synthesis and catabolism enzymes

Essential amino acids are in Capitals

K→acetyl-CoA

LYSINE→	Saccharopine dehydrogenase Glutaryl-CoA dehydrogenase

LEUCINE→	Branched chain aminotransferase Branched-chain alpha-keto acid dehydrogenase complex Isovaleryl coenzyme A dehydrogenase Methylcrotonyl-CoA carboxylase Methylglutaconyl-CoA hydratase 3-hydroxy-3-methylglutaryl-CoA lyase

TRYPTOPHAN→	Indoleamine 2,3-dioxygenase/Tryptophan 2,3-dioxygenase Arylformamidase Kynureninase 3-hydroxyanthranilate oxidase Aminocarboxymuconate-semialdehyde decarboxylase Aminomuconate-semialdehyde dehydrogenase

PHENYLALANINE→tyrosine→	(see below)

G→pyruvate
→citrate

glycine→serine→	Serine hydroxymethyltransferase Serine dehydratase glycine→creatine: Guanidinoacetate N-methyltransferase Creatine kinase

alanine→	Alanine transaminase

cysteine→	D-cysteine desulfhydrase

threonine→	L-threonine dehydrogenase

G→glutamate→
α-ketoglutarate

HISTIDINE→	Histidine ammonia-lyase Urocanate hydratase Formiminotransferase cyclodeaminase

proline→	Proline oxidase Pyrroline-5-carboxylate reductase 1-Pyrroline-5-carboxylate dehydrogenase/ALDH4A1 PYCR1

arginine→	Ornithine aminotransferase Ornithine decarboxylase Agmatinase

→alpha-ketoglutarate→TCA	Glutamate dehydrogenase

Other	cysteine+glutamate→glutathione: Gamma-glutamylcysteine synthetase Glutathione synthetase Gamma-glutamyl transpeptidase glutamate→glutamine: Glutamine synthetase Glutaminase

G→propionyl-CoA→
succinyl-CoA

VALINE→	Branched chain aminotransferase Branched-chain alpha-keto acid dehydrogenase complex Enoyl-CoA hydratase 3-hydroxyisobutyryl-CoA hydrolase 3-hydroxyisobutyrate dehydrogenase Methylmalonate semialdehyde dehydrogenase

ISOLEUCINE→	Branched chain aminotransferase Branched-chain alpha-keto acid dehydrogenase complex 3-hydroxy-2-methylbutyryl-CoA dehydrogenase

METHIONINE→	generation of homocysteine: Methionine adenosyltransferase Adenosylhomocysteinase regeneration of methionine: Methionine synthase/Homocysteine methyltransferase Betaine-homocysteine methyltransferase conversion to cysteine: Cystathionine beta synthase Cystathionine gamma-lyase

THREONINE→	Threonine aldolase

→succinyl-CoA→TCA	Propionyl-CoA carboxylase Methylmalonyl CoA epimerase Methylmalonyl-CoA mutase

G→fumarate

PHENYLALANINE→tyrosine→	Phenylalanine hydroxylase Tyrosine aminotransferase 4-Hydroxyphenylpyruvate dioxygenase Homogentisate 1,2-dioxygenase Fumarylacetoacetate hydrolase tyrosine→melanin: Tyrosinase

G→oxaloacetate

asparagine→aspartate→	Asparaginase/Asparagine synthetase Aspartate transaminase

Transferase: nitrogenous groups (EC 2.6)

2.6.1: Transaminases	Aspartate transaminase GOT1 GOT2 Alanine transaminase GABA transaminase Tyrosine aminotransferase Ornithine aminotransferase Branched chain aminotransferase Alanine—glyoxylate transaminase AGXT

2.6.3: Oximinotransferases	Oximinotransferase

2.6.99: Other	Pyridoxine 5'-phosphate synthase

Proteins: enzymes

Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Catalytically perfect enzyme Coenzyme Cofactor Enzyme catalysis Enzyme kinetics Lineweaver–Burk plot Michaelis–Menten kinetics

Regulation	Allosteric regulation Cooperativity Enzyme inhibitor

Classification	EC number Enzyme superfamily Enzyme family List of enzymes

Types	EC1 Oxidoreductases(list) EC2 Transferases(list) EC3 Hydrolases(list) EC4 Lyases(list) EC5 Isomerases(list) EC6 Ligases(list)

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