Direct involvement of hydrogen peroxide in bacterial alpha-hydroxylation of fatty acid.

We have reported that fatty-acid alpha-hydroxylase partially purified from Sphingomonas paucimobilis required NADH and molecular oxygen. In this study, we found that the reaction was greatly inhibited by catalase. Glutathione and glutathione peroxidase also inhibited alpha-hydroxylation, but superoxide dismutase and mannitol did not. Replacement of NADH and molecular oxygen by hydrogen peroxide increased the alpha-hydroxylation activity. In the presence of hydrogen peroxide, molecular oxygen was not required for the activity. These findings suggest that hydrogen peroxide was essential for bacterial alpha-hydroxylase.