Effect of linear energy transfer on the radiation-induced inactivation of dilute aqueous ribonuclease solutions

Abstract

The radiation-induced inactivation of dilute aqueous solutions of ribonuclease has been measured for radiations having a wide variation of LET. The results show that the radiation sensitivity of RNase falls as LET increases in the same way as the free radical yields decrease. However, there appears to be an additional decrease in sensitivity which is associated with the large size of the enzyme molecule. The results obtained with the 105 MeV ¹⁴N⁵⁺ ion are consistant with the concept of Mozumder, Chatterjee and Magee, that above a threshold velocity the track core diameter of heavy ions increases with increasing velocity.