Pseudomonas methanica

Leadbetter, E.R. and Foster. J.W. Oxidation products formed from gaseous alkanes by the bacterium Pseudomonas methanica. Arch. Biochem. Biophys., 82 491-492, 1959. 

Direct incorporation of molecular oxygen as 02 (Imada et ai, 1967) shows that the initial reaction is catalysed by an oxygenase and necessarily depends on oxygen. The most favorable position for attachment is the Cl position. The only stable metabolic product which could be isolated is the homologous normal alcohol Besides this so-called C] oxidation, there exists as another possibility, C2 oxidation. It could be shown from the example of Pseudomonas methanica that propane is oxidized into a mixture of propionic acid and acetone. In this case, R-alkanes are converted by intact cells into methyl ketone and also into the corresponding fatty acid. Other assumptions postulate that the C2 oxidation occurs on the basis of an equilibrium between the radicals of the Cl and C2 positions. 

Kemp, M. B., and J. R. Quayle Incorporation of Cj units into allulose phosphate by extracts of Pseudomonas methanica. Biochem. J. 99, 41 (1966). 

Fig. 2. Proposed path of oxidation of gaseous alkanes by Pseudomonas methanica (Sohngen) (Leadbetter and Foster, 1960).

Unlabeled propane was oxidized to acetone by Pseudomonas methanica and Mycobacterium smegmatis 422, respectively, in a medium enriched in deuterium oxide (Lukins and Foster, 1960). The isolated acetone was not significantly labeled, as it would have been had the following reaction sequence occurred (Eq. 3) ... 

Pyrroloquinoline quinone (PQQ) (or methoxatin) 6 is a coenzyme, responsible for the oxidation of methanol [7]. It has been found that cyclopropanol 4 inactivates the enzyme from M. methanica [8], the dimeric methanol dehydrogenase and the monomeric enzyme from a Pseudomonas PQQ-dependent methanol dehydrogenase [9] by forming adducts such as 7, through a one-electron oxidation process and the ready ring opening of a cyclopropyloxonium radical, Eq. (3) [8,9]. 

---