[Structural and antigenic differences of pancreatic RNAse preparations modified by dextran ethers in an...

Preparations of pancreatic RNAase modified by dextrane derivatives were obtained in an azocombination reaction. The UV absorption spectra and amino acid analysis of the preparations revealed quantitative and qualitative differences in the sites of the enzyme binding to the polymeric matrix depending on modification conditions. The observed differences in the binding sites of modified RNAase may be related both to the differences in the primary structure or even in the secondary and ternary structure of the enzyme. The latter observation was confirmed in studies of the antigenic properties of modified preparations. The interrelationship of these preparations with antibodies raised against native RNAase and the comparison of the degree of their antigenicity suggest the influence of modification on the antigenic properties of the protein. The number of binding sites of the enzyme to the support can be determined, which would neutralize the antigen-stimulated effect of the support due to the screening of protein antigenic determinants.