Structural damage of gamma-irradiated ribonuclease revealed by thin-layer isoelectric focusing.

Ribonuclease, irradiated with 60Co gamma-rays in dilute aqueous solution or in the dry state, has been investigated with respect to its charge and size properties. Thin-layer isoelectric focusing revealed extensive change in irradiated RNase; new enzymatically-active components, mainly with isoelectric points lower than in unirradiated RNase were observed. Thin-layer gel chromatography indicated the formation of aggregates which are partially active enzymatically. Aggreation depended on enzyme concentration and was less in more dilute solutions-- at equal degrees of inactivation. Structural damage in the so-called 'native' monomers was revealed by thin-layer isoelectric focusing, their charge properties being distinctly modified.