| Literature DB >> 1731915 |
M J Warren1, C A Roessner, S Ozaki, N J Stolowich, P J Santander, A I Scott.
Abstract
The trimethylated intermediate of vitamin B12 (corrin) biosynthesis, precorrin-3, was produced from various 13C-enriched isotopomers of 5-aminolevulinic acid (ALA), using a multiple-enzyme system containing ALA dehydratase, porphobilinogen deaminase, uro'gen III synthetase, and the S-adenosyl-L-methionine-(SAM)-dependent uro'gen III methyltransferase (M-1) and precorrin-2 methyltransferase (M-2) in the presence of [13C]SAM. Structural analysis of the resulting product, precorrin-3, reveals a close similarity to precorrin-2 but with several subtle differences in the conjugated array of C = C and C = N bonds which reflect the presence of the new C-methyl group at C20 and its influence on the electronic distribution in the dipyrrocorphin chromophore. The implications of this structure for corrin biosynthesis are discussed.Entities:
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Year: 1992 PMID: 1731915 DOI: 10.1021/bi00117a043
Source DB: PubMed Journal: Biochemistry ISSN: 0006-2960 Impact factor: 3.162