Screening and purification of a novel transaminase catalyzing the transamination of aryl beta-amino acid from Mesorhizobium sp LUK

Abstract

Mesorhizobium sp. LUK, which utilizes 3-amino3-phenylpropionic acid as the sole source of nitrogen with high enantioselectivity (E(S)> 100), was isolated using enrichment culture. The enzyme involved in the utilization of (S)-3-amino3-phenylpropionic acid was confirmed to be a transaminase and was purified by 235-folds with a specific activity of 0.72 U/mg. The molecular weight of the purified protein was ca. 47 kDa and the active enzyme was determined as a dimer on gel filtration chromatography. The N-terminal sequence was obtained from the purified protein. Spontaneous decarboxylation of produced beta-keto acids was observed during the chiral resolution of 3-amino-3-phenylpropionic acid.