EFFECT OF GROWTH-CONDITIONS ON THE ACTIVITIES OF METHYLOTROPHIC ENZYMES IN METHYLOPHILUS W3A1

The specific activities of four methylotrophic enzymes were measured i n batch and chemostat cultures of Methylophilus W3A1. Methanol dehydro genase was a constitutive enzyme. Methylamine dehydrogenase was regula ted by an induction/repression mechanism. Trimethylamine dehydrogenase and dimethylamine monooxygenase were induced co-ordinately, probably by dimethylamine. Methanol completely prevented synthesis of the methy l-amine oxidising enzymes when ammonium was also present; the absence of ammonium relieved this repression. The significance of the results for the evolution of methylotrophic pathways in restricted facultative methylotrophs is discussed.