Purification of Synthetic Ribonuclease S-Peptide Derivatives by Specific Complex Formation on Columns of Ribonuclease S-Protein Bound to Agarose

Abstract Ribonuclease S-protein was attached covalently to agarose which had been activated by treatment with cyanogen bromide according to the methods described by Porath and his colleagues. Columns made with this conjugate showed a high affinity for ribonuclease S-peptide, which could be recovered by elution with dilute acetic acid. This procedure, employed for the purification of synthetic S-peptide derivatives prepared by the solid phase method of Merrifield, resulted in marked enhancement of specific activity. However, the chemical and catalytic properties of the purified materials suggest the presence of closely related side products, formed during the synthesis or during subsequent deprotection steps which bind tightly to the S-protein conjugate but which yield enzymically inactive complexes with RNase S-protein.