Role of base-pairing in the control of an enzyme reaction.

In an attempt to ascertain whether specific base-pairing could have a regulating function in an enzyme system in which nucleotides serve as the substrate, we studied the effects of the addition of the various homopolymers of the ribonucleotide series on the action of adenylate kinase on ADP or CDP, and found that the results support this possibility. Poly U strongly inhibits the enzyme action on ADP, and poly G that on CDP, both to the extent of about 70 per cent. Lesser effects are shown when poly G is used with ADP and poly U with CDP. The other homopolymers tested, poly A and poly C, are ineffective.