Absorption Changes and Decays of Transients in Irradiated Papain

Summary

Pulse-radiolysis studies of aqueous papain solutions have been made over the 50 µs to 0·40 s time-scale and the 300 to 500 nm wave-length range. For the intermediates formed from both e⁻_aq and OH, the observed changes in optical density over the above time-scale are independent of papain concentration and dose per pulse. They are attributed to sequences of reactions within the same papain molecule. The overall conclusions are similar to those reported previously for the decay of ribonuclease intermediates (Lichtin, Ogdan and Stein 1972) and their implications for the interpretation of the mechanism of ⁶⁰Co inactivation of papain are pointed out.