OAM_alpha is the 12.8kDa, alpha subunit of d-ornithine 4,5-aminomutase, or OAM, an enzyme that converts d-ornithine to 2,4-diaminopentanoic acid by way of radical propagation from an adenosylcobalamin to a pyridoxal 5'-phosphate cofactor. OAM is an alpha2-beta2 heterodimer comprising two strongly associating subunits. The packing of the alpha subunits against the beta helps to form the substrate and co-factor binding-regions [1].

1: Large-scale domain dynamics and adenosylcobalamin reorientation orchestrate radical catalysis in ornithine 4,5-aminomutase. Wolthers KR, Levy C, Scrutton NS, Leys D; J Biol Chem. 2010;285:13942-13950. PMID:20106986