Coenzyme F420 is a hydride carrier cofactor that functions during methanogenesis. This family of proteins represents CofC, a nucleotidyl transferase that is involved in coenzyme F420 biosynthesis. CofC has been shown to catalyse the formation of lactyl-2-diphospho-5'-guanosine from 2-phospho-L-lactate and GTP [1].

1: Identification and characterization of the 2-phospho-L-lactate guanylyltransferase involved in coenzyme F420 biosynthesis. Grochowski LL, Xu H, White RH; Biochemistry. 2008;47:3033-3037. PMID:18260642