An inducible hydrolase from Mortierella isabellina (basidiomycetes). The deacylation of (+)-usnic acid |
| |
Authors: | James P Kutney Yutaka Ebizuka Phillip J Salisbury Chi-Kit Watt GHNeil Towers |
| |
Institution: | 1. Department of Chemistry, University of British Columbia, Vancouver, B.C. Canada;2. Department of Botany, University of British Columbia, Vancouver, B.C. Canada |
| |
Abstract: | An inducible enzyme catalysing the hydrolysis of (+)-usnic acid to (+)-2-desacetylusnic acid and acetic acid has been purified 150-fold from the mycelium of Mortierella isabellina grown in the presence of (+)-usnic acid. Purification was achieved by treatment with protamine sulfate, (NH4)2SO4 fractionation, negative adsorption on alumina Cγ gel and hydroxylapatite followed by chromatography on DEAE-cellulose and Sephadex G-200. The elution pattern from a Sephadex G-200 column indicated a MW of ca 7.6 × 104 for the enzyme. The apparent Km value for (+)-usnic acid at the pH optimum (pH 7) was 4.0 × 10?5 M. The enzyme was specific for (+)-usnic acid and inactive towards (?)-usnic acid, (+)-isousnic acid or certain phloracetophenone derivatives. Its activity was enhanced in the presence of divalent metal ions such as Co2+, Ni2+, Mn2+, Mg2+ and Zn2+. |
| |
Keywords: | Basidiomycetes inducible acylhydrolase (+)-usnic acid (+)-2-desacetylusnic acid acetic acid divalent cations |
本文献已被 ScienceDirect 等数据库收录! |
|