CHANGES IN BIOCHEMICAL-PROPERTIES OF OVOMUCOID BY RADIATION

Radiation effects on biochemical properties of ovomucoid, a protease i nhibitor which is a typical allergenic protein of egg, were investigat ed. Trypsin inhibiting activity of ovomucoid decreased exponentially a nd the inactivation was larger in N-2 than in O-2. The antigenicity of ovomucoid measured by ELISA was decreased exponentially and the inact ivation curves were almost the same as that of trypsin inhibiting acti vity. These results show that the oxygen protects the inactivation and destruction of antigenicity of ovomucoid while it enhances the reacti on with ovalbumin. The effect of radiolytically generated radical anio ns; a pronounced protective action of (CNS)(2)(-) and a slight acceler ate action of Br-2(-) were the same both on decrease in trypsin inhibi ting activity and antigenicity. SDS-PAGE showed that the change in pro tein structure was also protected by (CNS)(2)(-). These results sugges t that the changes by radiation were not mainly due to the destruction of essential amino acid residues but to the conformational change. Co pyright (C) 1996 Elsevier Science Ltd