Characterization of L-lysine 6-aminotransferase and its structural gene from Flavobacterium lutescens IFO3084

L-Lysine 6-aminotransferase (LAT) is an. enzyme involved in L-lysine catabo lism in a wide range of living organisms. LAT from Flavobacterium lutescens IFO3084 was purified, and its structural gene (lat) was cloned, sequenced and expressed in Escherichia coli. Native PAGE analysis of purified LAT gav e a single band corresponding to a molecular weight of about 110,000, Eat e ncoded a protein of 493 amino acids with a deduced molecular weight of 53,2 00, which is very close to that of purified LAT determined on SDS-PAGE. Exp ression of Eat in E. coli revealed that Eat encodes a single subunit protei n leading to LAT activity. These data suggested that LAT from F. lutescens IFO3084, like most other aminotransferases, is derived from a single ORF an d is active as a homodimer.