Oxidation of formaldehyde by alcohol oxidase of Candida boidinii

A fromaldehyde oxidase activity was found in cellfree extracts of methanol-grown yeast Candida boidinii. Loss of alcohol oxidase activity in a mutant, 48, led to loss of the formaldehyde oxidase activity, indicating that the same enzyme is probably responsible for both activities. This could be demonstrated with the purified alcohol oxidase which oxidizes, besides lower primary alcohols, formaldehyde to formate. The Km value for formaldehyde is 5.7 mM. It seems that alcohol oxidase is not implicated in formaldehyde oxidation in vivo.