Fig. 2.

SAM cleavage by NifB^Ma and NifB^Mt. HPLC elution profiles of (1) SAM, SAH, and 5′-dAH standards, (2) SAM alone, (3) SAM plus NifEN-B, (4) SAM plus NifB^Ma, and (5) SAM plus NifB^Mt. All samples contained dithionite. SAH was formed in the amounts of 0.20, 0.46, and 0.96 nanomole, respectively, per nanomole of NifEN-B, NifB^Ma, and NifB^Mt, whereas 5′-dAH was formed in the amounts of 0.18, 0.17, and 0.18 nanomole, respectively, per nanomole of NifEN-B, NifB^Ma, and NifB^Mt.