BOVINE PANCREATIC RIBONUCLEASE-SPECTROPHOTOMETRIC INVESTIGATIONS OF INTERACTION OF ENZYME WITH NUCLEOTIDES

Spectral changes on interaction of ribonuclease with a number of nucleotides have been measured. For guanine nucleotides these changes are the same as those produced by protonation of the guanine chromophore. It is concluded that the guanine ring of nucleotides interacts with an acid group of the protein in position N‐7. Evidence is presented for a similar interaction of the enzyme with the purine ring of adenine nucleotides. For uridine nucleotides the spectral changes on interaction with the enzyme are the same as those produced by de‐protonation of the pyrimidine ring in a partially hydrophobic environment. It is concluded that the pyrimidine ring of nucleotides interacts with a base group of the protein. The triphosphates of uridine, cytidine, guanine and adenine all form 1:1 ligand: enzyme complexes. Copyright © 1968, Wiley Blackwell. All rights reserved