Abstract
We studied the origin of the methyl group attached to C-2 of the pyrimidine moiety of thiamin (Pm) in Escherichia coil [3-^<13>C]glucose and [4-^<13>C]glucose were used as tracers and were incorporated into the ribose moiety of 5-aminoimidazole ribonucleotide(AIR), an intermediate of Pm via pentose phosphate pathway in E. coil The incorporation of these labels into Pm was examined, together with the measurment of the rate of the incorporation into histidine in E. coli. The label from [4-^<13>C]glucose was not incorporated into Pm, while the label from [3-^<13>C]glucose was effectively incorporated into it, indicating the incorporation of C-2 of ribose moiety of AIR into Pm. The biosynthetic conversion process from AIR to Pm in E. coli is proposed based on the results.
