Substrate Specificities of the Soluble and Particulate Methane Mono-oxygenases of Methylosinus trichosporium OB3b

Abstract

The intracellular location of methane mono-oxygenase (MMO) (soluble or particulate) in Methylosinus trichosporium OB3b is dependent on the availability of copper in the growth medium. Raising the Cu2+ concentration from 1 μm to 5 μm effected a transition from soluble to particulate MMO activity, and changes in major cell polypeptides were observed on SDS-polyacrylamide gels. Organisms containing soluble MMO oxidized a wide range of substrates including n-alkanes, n-alkenes, aromatic and alicyclic compounds. By contrast, organisms containing particulate MMO did not oxidize aromatic or alicyclic compounds. These observations provide further evidence that the two types of MMO are fundamentally different.