Clues for the existence of two different epoxide hydrolase activities in the fungus Beauveria bassiana

Epoxide hydrolase activity was produced during the exponential and stationa ry growth phases of the fungus Beauveria bassiana ATCC 7159. It was complet ely cell-associated. After cell disruption epoxide hydrolase activity was r ecovered in both the cell debris (EH "A") and the soluble fraction (EH "B") , but not in the membrane fraction. Activity assays of these fractions with two different substrates indicated that their substrate specificity, as we ll as the corresponding E value and, to a lesser extent, their regioselecti vity, were different. Also, we could observe that the absolute configuratio n of the residual epoxide was opposite. This indicates that these two epoxi de hydrolase activities are substantially different and are, therefore, int erestingly complementary biocatalysts for the preparation of the correspond ing epoxides and/or vicinal diols in nearly enantiopure form. (C) 2000 Else vier Science Inc. All rights reserved.