Abstract
I started my research career by studying mirobial aminotransferases to demonstrate and characterize a new enzyme, L-lysine 6-aminotransferase at Kyoto in 1960, and then found a novel function and regulatory mechanism of aspartate 4-decarboxylase at Boston. After returned home, I was engaged in research of various microbial pyridoxal enzymes such as alanine racemase, arginine racemase, amino acid rasemase with low subsrate specificity, taurin: α-ketoglutarate aminotransferase, kynureninase, methionine γ-lyase, selenocysteine β-lyase and D-amino acid aminotransferase, and NAD (P)-dependent amino acid dehydrogenases including thermostable leucine dehydrogenase and phenylalanine dehydrogenase. Methionine γ-lyase, lysine α-oxidase, leucine dehydrogenase and glutaminase showed antineoplastic activity. The stereochemical aspects of hydrogen transfer in aminotransferase and NAD-dependent dehydrogenase reactions, and thermostability of psychrophilic dehydrogenases were also studied. We demonstrated and characterized FAD-dependent 2-nitropropane dioxygenase and nitroalkane oxidase as well, and developed enzymatic enantiospecific production of amino acids.
