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Purification and characterization of an extracellular cholesterol oxidase from a Bordetella species

Paper ID Volume ID Publish Year Pages File Format Full-Text
34979 45064 2010 7 PDF Available
Title
Purification and characterization of an extracellular cholesterol oxidase from a Bordetella species
Abstract

A soil-isolated bacterium (strain B4) was identified as a species of Bordetella and deposited with the China General Microbiological Culture Collection (code, CGMCC 2229). The bacterium grew in a mineral medium, on cholesterol as a sole source of carbon and energy. Only one metabolite of cholesterol was accumulated in detectable amounts during the strain growth. It was identified as 4-cholesten-3-one. Cholesterol oxidase (COD) (EC 1.1.3.6), which catalyzes cholesterol into this metabolite, was evidenced from the strain. The conditions of the bacterium growth were optimized for extracellular enzyme production, which then reached around 1700 UL−1 within 24 h culturing. The enzyme was purified from the spent medium of the strain to homogeneity on SDS-PAGE, and characterized. Its molecular mass, as estimated by this technique, was 55 kDa. COD showed an optimum activity at pH 7.0. It was completely stable at pH 5.0 and 4 °C for 48 h, and retained 80% at least of its initial activity at pH 4.0 or at a pH of 6.0–10.0. The optimum temperature for its reaction was 37 °C. The thermal stability of COD was appreciable, as 90% or 80% of its initial activity was recovered after 1 h or 2 h incubation at 50 °C. Ag+ or Hg+ at 1 mM, was inhibitor of COD activity, while Cu2+, at the same concentration, was activator. The COD Km, determined at 37 °C and pH 7.0, was 0.556 mM. The enzyme was stable at pH 7.0 and 37 °C during 24 h mechanical shaking in the presence of 33% (v/v) of either of the solvents, dimethylsulfoxide, ethyl acetate, butanol, chloroform, benzene, xylene or cyclohexane.

Keywords
Bordetella species; Cholesterol; 4-Cholesten-3-one; Cholesterol oxidase; Purification; Characterization
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Purification and characterization of an extracellular cholesterol oxidase from a Bordetella species
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Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 45, Issue 9, September 2010, Pages 1563–1569
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us