title: Oxidation of methanol by facultative and obligate methylotrophs.
abstract: 1. The newly isolated methanol obligate Methylomonas sp. and the methanol facultative Pseudomonas sp. oxidize methanol at an unchanged rate over concentration range from 0.1 to 600 mM; the oxidation rate by the obligate methylotroph is 2.5 times higher (300 nmoles O2/min/mg dry wt.). Low-molecular alcohols, formaldehyde and formate serve as respiratory substrates for the intact cells of both methylotrophs. 2. Methanol dehydrogenase of both methylotrophs isolated should be classified as the phenazine methosulphate-dependent pteridine-type enzyme of double methanol-and formaldehyde-dehydrogenase function. This soluble enzyme is stimulated about 10-fold by NH+4, which results in enhancement of V max, and shows the same specificity and the same affinity toward methanol and formaldehyde (K m about 5 X 10(-5) M). Heat-inactivation of the 10-fold purified enzyme is associated with the release of a watersoluble pigment with maximum fluorescence at 420-430 nm. 3. NAD-deendent formate dehydrogenase was found to catalyse the third step of methanol oxidation in both methylotrophs.
mesh_terms: D000432:Methanol / Q000378:metabolism*; D008772:Methylococcaceae / Q000378:metabolism*; D009154:Mutation; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D011549:Pseudomonas / Q000378:metabolism*
chemical_list: D010088:Oxidoreductases; D000432:Methanol