Aerobic and Anaerobic Metabolism of Trimethylamine, Dimethylamine and Methylamine in Hyphomicrobium X

Abstract

Hyphomicrobium strain x was grown on trimethylamine and dimethylamine as the sole sources of carbon and energy under both aerobic and anaerobic conditions and the enzymes involved in the metabolism of these compounds were investigated. During aerobic growth of the organism on trimethylamine, accumulation and subsequent utilization of dimethylamine was observed. When the organism was grown on trimethylamine under anaerobic conditions in the presence of nitrate, a sequential accumulation and utilization of dimethylamine and methylamine was found. In cell-free extracts of Hyphomicrobium x grown on trimethylamine or dimethylamine under both aerobic and anaerobic conditions the following enzyme activities were detected : trimethylamine dehydrogenase, dimethylamine dehydrogenase, y-glutamylmethylamide synthetase, N-methylglutamate dehydrogenase, methanol dehydrogenase, formaldehyde dehydrogenase, formate dehydrogenase and hydroxypyruvate reductase. Under neither growth condition were any of the following enzyme activities detected : trimethylamine mono-oxygenase, dimethylamine monooxygenase, trimethylamine-N-oxide aldolase (demethylase) and primary-amine dehydrogenase. Trimethylamine dehydrogenase and dimethylamine dehydrogenase were partially purified from bacteria grown on dimethylamine and the results suggest that in Hyphomicrobium x a novel enzyme, namely dimethylamine dehydrogenase, participates in the oxidation of dimethylamine.

Dimethylamine Dehydrogenase from Hyphomicrobium X: Purification and Some Properties of a New Enzyme that Oxidizes Secondary Amines

“…These have been described previously (Meiberg & Harder, 1978). Purification of dimethylamine dehydrogenase.…”

“…Recently, it was shown that during anaerobic growth of Hyphomicrobium X on trimethylamine and dimethylamine in the presence of nitrate, dimethylamine is oxidized by a dimethylamine dehydrogenase (Meiberg & Harder, 1978). The evidence indicated that this was a new enzyme.…”

“…The evidence indicated that this was a new enzyme. There have been previous reports on dimethylamine dehydrogenase activity, but these refer to the ability of purified trimethylamine dehydrogenase to oxidize the substrate at low rates (Colby &Zatman, 1974;Meiberg & Harder, 1978).…”

“…Special attention is paid to those kinetic parameters which might explain the rather complicated pattern of substrate utilization which occurs during anaerobic growth of this organism on trimethylamine (Meiberg & Harder, 1978).…”

Synthesis of Certain Assimilatory and Dissimilatory Enzymes during Bacterial Adaptation to Growth on Trimethylamine

“…Trimethylamine may be converted to dimethylamine via trimethylamine N-oxide (Boulton, Crabbe & Large, 1974) or directly via a dehydrogenase-cataly sed reaction (Colby & Zatman, 1973. Dimethylamine may be converted to methylamine either via a monooxygenase (Eady, Jarman & Large, 1971) or via a dehydrogenase (Meiberg & Harder, 1976). Methylamine oxidation may proceed directly (Eady & Large, I 97 I) or via N-methylglutamate (Hersh, Peterson & Thompson, 1971 ;Bamforth & Large, 1977) and/or N-methylalanine (Lin & Wagner, 1975.…”