Members of this protein family are the alpha subunit of methyl coenzyme M reductase, also called coenzyme-B sulfoethylthiotransferase (EC 2.8.4.1). This enzyme, with alpha, beta, and gamma subunits, catalyzes the last step in methanogenesis. Several methanogens have encode two such enzymes, designated I and II; this model does not separate the isozymes. [Energy metabolism, Methanogenesis]
Jiyao W et al.(2023). "The conserved domain database in 2023.",