Purification and characterization of Rhodococcus boritolerans FW815 nitrile hydratase

Abstract

Rhodococcus boritolerans FW815 has strong nitrile hydratase activity towards racemic 2, 2-dimethylcyclopropanecarbonitrile. In this work, the nitrile hydratase enzyme (NHase) was purified from R. boritolerans FW815. Results demonstrate that the purified NHase consists of two different subunits with molecular weights of 24 kDa and 22 kDa, respectively. Analytical size exclusion chromatography analysis reveals that this NHase has a molecular weight of 40 kDa. The purified nitrile hydratase enzyme is most active at 37°C, pH 7.0, while Cu2+, Zn2+, Ni2+ and ethylenediaminetertaacetic acid (EDTA) display inhibitory effects on its activity. In addition to 2, 2-dimethylcyclopropanecarbonitrile and 2-amino-2, 3-dimethylbutyronitrile, it can efficiently hydrate 2-(2-oxopyrrolidin-1-yl) butyronitrile, acrylonitrile and 2-amino-4-methylthio-1-butyronitrile.