[Primary metabolic pathways of methylated amines in Hyphomicrobium vulgare]

As was established by isotopic and ezymatic studies, there are some common features and certain differences in primary metabolic pathways of methanol, methylamine and trimethylamine in Hyphomicrobium vulgare ZV. Assimilation of the carbon of these compounds at the level of formaldehyde through the serine cycle is in common, formaldehyde being partly oxidized to CO2. The differences are manifested in the steps of conversion of C1-substrates prior to formaldehyde formation. The carbon of methanol enters the serine cycle immediately after the oxidation to formaldehyde. In the case of methyl-amine N-methylation of glutamate firstly occurs and gamma-glutamylmethylamide and N-methylglutamate are formed. Trimethylamine is oxidized by phenazine methosulphate-linked dehydrogenase to dimethylamine and then to methylamine by NADPH-dependent mono-oxygenase. Here two formaldehyde units are liberated which enter directly the serine cycle. The third formaldehyde unit is formed from methylamine via N-methyl-glutamate pathway.