cDNA cloning, genomic structure, chromosomal mapping, and functional expression of a novel human alanine aminotransferase.

Article Details

Citation

Yang RZ, Blaileanu G, Hansen BC, Shuldiner AR, Gong DW

cDNA cloning, genomic structure, chromosomal mapping, and functional expression of a novel human alanine aminotransferase.

Genomics. 2002 Mar;79(3):445-50.

PubMed ID
11863375 [ View in PubMed
]
Abstract

Alanine aminotransferase (ALT) catalyzes the reversible transamination between alanine and 2-oxoglutarate to form pyruvate and glutamate, and thereby has a key role in the intermediary metabolism of glucose and amino acids. Two ALT isoenzymes are known to exist, but only one ALT gene has been cloned, GPT. In this study, we cloned a homolog of GPT and named it GPT2, and the corresponding protein ALT2. GPT2 shares 69% identity and 78% similarity at the protein level to the previously cloned GPT. The human gene GPT2 encodes a 3.9-kb mRNA, consists of 12 exons, spanning approximately 50 kb of the genome, and maps to chromosome 16q12.1. GPT2 and GPT differ in mRNA expression in that GPT2 is highly expressed in muscle, fat, and kidney, whereas GPT is mainly expressed in kidney, liver, and heart. In addition, GPT2 seems to be the predominant form of GPT at the mRNA level in these tissues. Expression of ALT2 protein in Escherichia coli produced a functional recombinant enzyme that catalyzes alanine transamination, confirming that the enzyme is an ALT. The more abundant expression of GPT2 than GPT, especially in muscle and fat, suggests a unique and previously unrecognized role of this gene product in glucose, amino acid, and fatty acid metabolism and homeostasis.

DrugBank Data that Cites this Article

Drug Targets
DrugTargetKindOrganismPharmacological ActionActions
AlanineAlanine aminotransferase 2ProteinHumans
Unknown
Not AvailableDetails
Polypeptides
NameUniProt ID
Alanine aminotransferase 1P24298Details
Alanine aminotransferase 2Q8TD30Details