Biosynthesis of vitamin B12: mode of incorporation of factor III into cobyrinic acid
- C Nussbaumer,
- M Imfeld,
- G Wörner,
- G Müller, and
- D Arigoni
Abstract
Extensive chemical degradation of cobyrinic acid biosynthesized from a sample of factor III radiochemically labeled in its three methyl groups demonstrates that label is retained exclusively in the two methyl groups at positions C-2 and C-7 and confirms that the C-20 methyl group of the precursor is lost during formation of the corrin ring system.
