The Interaction of Ribonuclease with Metal Ions: III. GEL FILTRATION STUDIES ON THE RELATIONSHIP BETWEEN CUPRIC ION AND CYTIDYLIC ACID BINDING

摘要: Abstract The effect of 2'-cytidylic acid and 3'-cytidylic upon the binding cupric ions by RNase has been studied gel filtration, together with 2'- acids. results confirm that 2'-CMP weakens its affinity for ions; reciprocally, ion diminishes 2'-CMP. negative interactions between to have shown lead distortion filtration ligand trough. At pH 5.5 these are tentatively interpreted in terms competition Cu(II) strongest Cu(II)-binding site on an acetate-dependent increase one weaker sites presence bound Binding 3'-CMP increases 2 similarly 3'-CMP. Analysis pattern 3'-CMP-RNase complex indicates co-operative two complex; at least differs from any free could involve phosphate group In further contrast RNase, a diminished ion-monoacetate relative ion. This suggests that, average, is coordinated more ligands than or, alternatively, occurs sterically limited environment RNase.