Inhibition of pancreatic ribonuclease by 2'-5 ' and 3'-5 ' oligonucleotides

Forty d i f fe rent oligonucleotides were investigated as possible Inhibi tors of the depolymerizing ac t i v i t y of RNase A. The strongest inh ib i tors among the diribonucleoside 2 '-5 ' mono- phosphates were: G2'-5'G, C2'-5'G and U2'-5'G, and among the diribonucleoside 3 '-5 ' monophosphates: ApU, ApC and GpU. Of the eight tr inucleot ides investigated, ApApUp, ApApCp and ApGpUp were the strongest inh ib i to rs. A l l four dinucleotides studied (ApUp, ApCp, GpUp and GpCp) were very strong i nh ib i t o rs, ApUp being the strongest one. The results show that the nature of the various bases in the o l i go-nucleotide has an ef fect on the degree of Inh ib i t i on, and that the 3 ' phospho-monoester group Increases the binding of the oligonucleotide to RNase A. These Inhibi tors can be used 1n physicochemical and biochemical studies of Hbonuclease