Substrate specificity and stereoselectivity of fatty alcohol oxidase from the yeast Candida maltosa
In Candida maltosa and other alkene-utilizing yeasts a membrane-bound fatty alcohol oxidase (FAOD) is induced by growth on n-alkenes. The oxidation of 1-alkanols to the corresponding aldehydes is accompanied by the stoichiometric consumption of 1 mol O2 and formation of 1 mol hydrogen peroxide (H2O2). The FAOD of C. maltosa shows a broad substrate specificity. It catalyses the oxidation of 1-alkanols (C4 to C22), with a maximal activity of 1.85 gmmol H2O2/ min × mg protein for 1-octanol, as well as the transformation of 2-alkanols (C8 to C16) to ketones. Other compounds as α,ω-alkenediols, ω-hydroxypalmitic acid, phenylalkanols and terpene alcohols are substrates for the enzyme, although mostly with decreased activities. The oxidation of the racemic 2-alkanols by the FAOD proceeds with very high stereoselectivity for the R(−)-enatiomers only, leaving the S(+)-2-alkanol untouched.