Evaluation of biosynthetic pathways to δ-aminolevulinic acid in Propionibacterium shermanii based on biosynthesis of vitamin B12 from D-[1-13C]glucose

Analysis of the C-13 nuclear magnetic resonance (NMR) spectrum of C-13-labeled vitamin B-12 biosynthesized from D-[1-C-13]glucose by Propionibacterium shermanii provided evidence suggesting that delta-aminolevulinic acid (ALA) incorporated in the C-13-labeled vitamin B-12 may have been synthesized via both the Shemin pathway and the C5 pathway under anaerobic conditions in the ratio of 1 < [(ratio of ALA biosynthesis from the Shemin pathway)/(that from the C5 pathway)] < 1.8. The D-ribose moiety of vitamin B-12 was labeled with C-13 at R-1, R-3, and R-5. The aminopropanol moiety of vitamin BI was labeled on Pr-1 and Pr-2, but not Pr-3.