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The conversion of α-methyleneglutarate (αMG) to dimethylmaleate (DMM) via methylitaconate (MeIT) is the reaction sequence that produces a symmetrical intermediate in the fermentation of nicotinic acid by Clostridium barkeri. αMG mutase catalyzes the isomerization of αMG in a B12coenzyme-dependent reaction to form MeIT which in turn is isomerized to DMM by MeIT isomerase. Both enzymes are induced by growth on nicotinic acid and are not detectable in cells grown on glucose. The isomerase reaction favors the formation of DMM, whereas the mutase reaction favors the formation of αMG. Both reactions were demonstrated to be reversible. αMG mutase activity was assayed by coupling the formation of MeIT with the production of DMM in the presence of the isomerase. The purified mutase has an absolute requirement for cobamide coenzyme. The apparent Kmvalues for αMG, α-(5,6-dimethylbenzimidazolyl)-cobamide coenzyme, α-(benzimidazolyl)-cobamide coenzyme, and α-(adenyl)-cobamide coenzyme are 7.14 x10-3, 7.3 x10-8, 3.0 x10-7, and 1.25 x10-6m, respectively. The most effective coenzyme, α-(5,6-dimethylbenzimidazolyl)cobamide coenzyme, is the same one that is synthesized in large amounts when C. barkeriis grown on nicotinic acid.

The DNA-directed in vitrosynthesis of β-galactosidase has been examined in a system dependent on Escherichia coliribosomes, a salt wash of the ribosomes, and a 200,000 xgsupernatant fraction. The ribosomes can be replaced by 30 S and 50 S ribosomal subunits. Extraction of the 50 S particles with ethanol-NH4yields inactive particles which can be reactivated equally well by the addition of either ribosomal protein L7or L12.

Pseudomonas sp. MS is capable of growth on a number of compounds containing only C1 groups. They include trimethylsulphonium salts, methylamine, dimethylamine and trimethylamine. Although formaldehyde and formate will not support growth they are rapidly oxidized by intact cells. Methanol neither supports growth nor is oxidized. A particulate fraction of the cell oxidizes methylamine to carbon dioxide in the absence of any external electron acceptor. Formaldehyde and formate are more slowly oxidized to carbon dioxide by the particulate fraction, although they do not appear to be free intermediates in the oxidation of methylamine. Soluble NAD-linked formaldehyde dehydrogenase and formate dehydrogenase are also present. The particulate methylamine oxidase is induced by growth on methylamine, dimethylamine and trimethylamine, whereas the soluble formaldehyde dehydrogenase and formate dehydrogenase are induced by trimethylsulphonium nitrate as well as the aforementioned amines.