Thermostable Aminoacylase from Bacillus thermoglucosidius: Purification and Characterization†

Abstract

We studied the distribution of aminoacylase, an enzyme catalyzing the hydrolysis of N-acylamino acids, in thermophilic bacteria, and found Bacillus thermoglucosidius DSM 2542 to be the best producer of the enzyme. The enzyme, purified 13,400-fold to homogeneity in an overall yield of 34%, has a molecular weight of about 175,000, and is composed of four subunits identical in molecular weight (43,000). The enzyme contains 4g atoms of zinc per mol of enzyme protein. The enzyme catalyzes hydrolysis of various kinds of N-acyl-L-amino acids with very high molecular activity compared to those of fungal and mammalian enzymes: Vmax and Kmfor N-acetyl-L-methionine are 3410 units/mg protein and 7.9 mM, respectively. Great stability at high temperatures and with organic solvents and protein denaturants is a characteristic of the enzyme. © 1987, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.