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A calorimetric approach to the study of the interactions of cytidine‐3′‐phosphate with bovine seminal ribonuclease
Author(s) -
Ambrosino Rita,
Barone Guido,
Castronuovo Giuseppina,
Cultrera Orazio,
Di Donato Alberto,
Elia Vittorio
Publication year - 1989
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360280806
Subject(s) - chemistry , cytidine , ribonuclease , bovine pancreatic ribonuclease , phosphate , biochemistry , enzyme , rna , gene
A calorimetric study at 25°C is reported on the interaction between allosteric bovine seminal ribonuclease and cytidine‐3′‐phosphate. The results are compared with those obtained under identical experimental conditions for the interaction of pancreatic ribonuclease A and the same nucleotide. The analysis of the data provides evidence that the binding sites of seminal ribonuclease for cytidine‐3′‐phosphate are not equivalent, in agreement with previous equilibrium dialysis studies. A model with two sites with different affinities toward the nucleotide, the site with higher affinity resembling the binding site of pancreatic ribonuclease, is proposed. The values calculated for the thermodynamic parameters provide an insight of the forces involved in the interaction of the two enzymes with the nucleotide.