Cholesterol esterase produced by Streptomyces lavendulae.

Cholesterol esterase was purified from the culture filtrate of Streptomyces lavendulae by a procedure involving precipitation with ammonium sulfate and acetone, gel filtration on Sepharose CL-4B, and rechromatography on Sepharose CL-4B after treatment of Triton X-100. The purified enzyme was detected as a single band by polyacrylamide disc electrophoresis, while one main band and three minor bands were observed by SDS gel electrophoresis. The molecular weight of the main band was 29000. The enzyme was inhibited by Hg2+, Ag+ and DFP. Long-chain fatty acid esters of cholesterol were hydrolyzed preferentially and pH optimum was 6.0. This enzyme could be used to the determination of total serum cholesterol with cholesterol oxidase from Streptomyces violascens.