[On the preparation of intermediates in cobyrinic acid biosynthesis by suspensions of Propionibacterium shermanii (author's transl)].

The preparation of a dimethyltetrahtdrouroporphyrin (Faktor II or sirohydrochlorin) using suspensions of Propionibacterium shermanii as well as a promising method for the isolation of tetrapyrrols with at least four carboxy substituents from cell-free extracts and growth media are described. Also a Faktor II-analogue with three methyl groups which are derived from L-methionine is reported. Incorporation experiments indicate that this is an intermediate in cobyrinic acid formation. Because of this, and from spectroscopic (field desorptionmass, visible absorption) studies it is concluded that the "extra" methyl group is located at the meso-carbon between two methylated reduced rings.