[Primary oxidation mechanisms in degradation of aliphatic hydrocarbons by bacterial enzyme systems (author's transl)]

The bacterial dissimilation of aliphatic hydrocarbons is catalysed by a monooxygenase mechanism with incorporation of molecular oxygen. Numerous publications have shown the cytochrome P 450-dependent hydroxylation of hydrocarbons, but there is considerably less information of hemo-protein-independent hydroxylations by alkanhydroxylases. In a marine Pseudomonad we found a system sensitive to cyanide: The oxygenase could be divided into three protein fractions. A cytochrome P 450 type spectrum was not detected. The NADH-dependent hydroxylation of n-decane can be activated by Mg2+ and Fe2+ ions. A noncompetitive product inhibition occurs which deserves special attention. An alcohol-dehydrogenase is closely associated with the oxygenase system by a kind of multienzyme-complex. Studies on kinetics and substrate specificity of this enzyme show an inhibition by excess substrate increasing with the chain length of the alcohols. The whole complex (alkanhydroxylase, alcoholdehydrogenase and aldehyddehydrogenase) is induceable by bacterial growth on alkanes, primary alcohols and fatty acids as sole carbon source.