This protein family includes several components of multicomponent enzyme systems predominantly found in Proteobacteria and Actinobacteria, including subunits alpha and beta of a methane monooxygenase and an alkene monooxygenase system, small and large subunits of propane 2-monooxygenase system and P1 protein of phenol hydroxylase [1-4].

1: Localization and organization of phenol degradation genes of Pseudomonas putida strain H. Herrmann H, Muller C, Schmidt I, Mahnke J, Petruschka L, Hahnke K; Mol Gen Genet 1995;247:240-246. PMID:7753034

2: Crystal structures of the soluble methane monooxygenase hydroxylase from Methylococcus capsulatus (Bath) demonstrating geometrical variability at the dinuclear iron active site. Whittington DA, Lippard SJ; J Am Chem Soc. 2001;123:827-838. PMID:11456616

3: An inducible propane monooxygenase is responsible for N-nitrosodimethylamine degradation by Rhodococcus sp. strain RHA1. Sharp JO, Sales CM, LeBlanc JC, Liu J, Wood TK, Eltis LD, Mohn WW, Alvarez-Cohen L; Appl Environ Microbiol. 2007;73:6930-6938. PMID:17873074

4: Alkene monooxygenase from Xanthobacter strain Py2. Purification and characterization of a four-component system central to the bacterial metabolism of aliphatic alkenes. Small FJ, Ensign SA; J Biol Chem. 1997;272:24913-24920. PMID:9312093