Well, that's where vitamin B twelve actually comes into play. So part of that vitamin B twelve molecule is shown in this diagram and it contains a radical. So we have a single electron on this carbon. Now remember from organic chemistry that radicals are very reactive. And what happens in this particular case is the vitamin B twelve is used by this mutase enzyme to help abstract an h atom from this methyl group. So we essentially take away this h atom, we take away the one electron with that h atom and we basically help form a sigma bond, a single bond between the H and the carbon as shown in this particular diagram.