Corynebacterium sarcosine oxidase is composed of A, B, C, and D subunits. To characterize these subunits, we analyzed their N-terminal sequences by automated Edman degradation. We identified 20 residues of subunit A, 58 of B, 31 of C, and 33 of D. There was no homology among these sequences according to secondary structure predictions and hydrophilicity profiles. But we found that subunit B contained a sequence homologous to that of the AMP-binding site of other flavoproteins.