Abstract
The DPN is a cofactor for the polynucleotide-joining enzyme from E. coli. The apparent Km (1 x 10-7 [image]) is of the same order of magnitude as the Km for the polydeoxythymidylate substrate (2.5 x 10-8 [image]); DPNH and the thionicotinamide derivative of DPN while active had Km values 7-fold greater than DPN. The other analogues of DPN including TPN were inactive.