Effects of detergents on specific activity and enantioselectivity of the epoxide hydrolase from Rhodotorula glutinis

The yeast Rhodotorula glutinis contains an enantioselective epoxide hydrolase. Previous work showed that the enzyme is a membrane-associated enzyme that can be solubilised from the membranes by a detergent treatment. Now, the effect of detergents on reaction rate and particularly enantioselectivity was investigated. Three types of detergents were tested: non-ionic, anionic and zwitterionic. Non-ionic detergents stimulated the specific activity of the enzyme. Enantioselectivity of the enzyme was strongly affected by several detergents. Thesit and sucrosemonolaurate had the most pronounced effects and enantiomeric ratios were strongly enhanced. The effects are most likely due to the ability of detergents to stabilise membrane-proteins by forming micelles and thus mimicking the membrane structure.