Pyridine Nucleotide Metabolism in Escherichia coli

Abstract

Abstract The pyridine nucleotide pool of Escherichia coli is made up almost exclusively of DPN and TPN. In an exponentially growing glucose culture an average cell contains 1,460,000 molecules of DPN (30% reduced) and 440,000 molecules of TPN (57% reduced). If the total volume of the cell were accessible to pyridine nucleotide, this would mean a total DPN concentration of 1.3 x 10-3 m and a TPN concentration of 3.9 x 10-4 m. During exponential growth, in an average cell, 550 DPN molecules are being synthesized from external niacin, 270 DPN molecules are being transformed to TPN, and 140 TPN molecules are being broken down (to DPN) each second.