[Molecular biological aspects of amino acid metabolizing enzymes]

This article briefly describes the molecular biological aspect of studies on some enzymes involved in amino acid metabolism. Aspartate aminotransferase is one most extensively studied enzyme. Together with its three dimensional structure, recent studies using site-directed mutagenesis have led to the understanding of its structure-function relationships. Successful cDNA cloning of other aminotransferase has enabled us to understand the degree of homology in amino acid sequence. cDNAs for several amino acid decarboxylases were also cloned. Genomic structures for the enzymes involved in urea cycle have been studied. These studies have provided a molecular basis for some hyperammonemias. Its is strongly anticipated that the understanding of other metabolic disorders may be promoted by further accumulation of molecular biological data on the relevant enzymes.