[Kinetic parameters of hydrolysis of CpA and UpA sequences in an oligoribonucleotide by compounds functionally mimicking ribonuclease A]. / Kineticheskie parametry gidroliza CpA- i UpA-posledovatel'nostei v sostave ribooligonukleotida pod deistviem soedinenii, funktsional'no imitiruiushchikh ribonukleazu A.

Kinetic parameters of cleavage of CpA and UpA sequences in an oligoribonucleotide under the action of artificial ribonuclease ABL3C1 were measured. The compounds were built of RNA-binding domain B, catalytic fragment C, linker L3 comprising 3 methylene groups, and aliphatic fragment A. The rate of cleavage of phosphodiester bonds in CpA sequence within decaribonucleotide UUCAUGUAAA was shown to be 3.4 +/- 0.2 times higher than in UpA sequence. The rate of cleavage of phosphodiester bonds were found to depend on substrate length: a thousandfold increase in cleavage rate constant was observed for CpA sequence in decaribonucleotide as compared with diribonucleotide monophosphate CpA. A slight decrease in the cleavage rates was observed for the reactions proceeding in different buffers at pH 7.0: imidazole > HEPES > phosphate > cacodylate. At the same time, the ratio of cleavage rates for CpA and UpA sequences remained constant.