[Cobalamins and tRNA methyltransferase activity in E. coli cells]

The end of the logarithmic phase of growth of E. coli 113-3 cells in a mineral medium with methylcobalamin (MeCbl) occurs 60 minutes earlier than in the case of cells grown with cyancobalamin (CNCbl). Chromatography on a Sephadex - DEAE cellulose column of the 105 000xg fractions of cell-free extracts of the cells grown in the presence of MeCbl showed both quantitative and qualitative differences. The ability of individual protein fractions to transfer the 14CH3-groups from the Adomet to submethylated tRNA of E. coli K12W6 in the cells grown with MeCbl increases 1.5 - 3-fold in comparison with those grown with CNCbl. A chromatographic analysis of methylated bases of tRNA did not show any qualitative differences. In the presence of MeCbl the incorporation of the CH3-groups into m7G is increased by 50%.