Phenylglyoxal, an
arginine-specific
reagent, strongly inhibits
DNA polymerases isolated from eukaryotic, prokaryotic, and
RNA tumor viral sources as well as Escherichia coli
RNA polymerase. The inhibitory action of
phenylglyoxal appears to be due to interference with the template binding function of these
enzymes and implies the presence of an
arginine residue at the template binding site of these
enzymes from diverse sources and suggests that template dependent
DNA, and perhaps
RNA polymerases, may be mechanistically similar with respect to their template binding function. In contrast, the activity of
terminal deoxynucleotidyl-transferase, a template-independent
DNA polymerase isolated from calf thymus, is not inhibited by
phenylglyoxal. A detailed analysis of the inhibitory process carried out using avian myeloblastosis virus (AMV)
DNA polymerase as a test
enzyme revealed that inclusion of template-primer during the preincubation with
phenylglyoxal, but not substrate triphosphates or primer alone, protects the
enzyme against
phenylglyoxal inactivation. Furthermore,
phenylglyoxal does not appear to inhibit the elongation of initiated
DNA strands, but blocks the reinitiation of
DNA synthesis.