Abstract
A coryneform bacterium, strain A-1, produced extracellularly an aryl acylamidase, which was markedly activated by preincubation with a substrate, acetanilide (AAN). This specific enzyme was purified by ammonium sulfate fractionation under the coexistence of AAN, followed by chromatographic fractionations with DEAE-Sephadex A-50 and Sephadex G-100. The enzyme purified 263 fold over crude preparation gave a single band on SDS-PAGE. The molecular weight was estimated to be ca. 127, 000, which was appreciably larger than those of known bacterial aryl acylamidases. The activated enzyme tended to be more tolerant of high temperatures and some metal ions, compared with the nonactivated one. This purified and activated enzyme also hydrolyzed aniline-based pesticides such as naproanilide, chlorpropham, propanil and linuron. Kinetic analysis of substrate-saturation curves of these chemicals showed that the compound's overall ability to act as a substrate was higher for chemicals having unsubstituted aniline moiety than for ones having Cl-substituted aniline moiety in the molecule. It was strongly suggested that the enzyme conformation was induced to fit readily for unsubstituted acylanilides due to the activation with AAN.
