Effects of Oxygen and Sulphydryl-containing Compounds on Irradiated Transforming DNA. III. Reaction Rates

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Abstract
The absolute rate for the repair reaction of radiation-induced, O2-dependent lesions in bacterial [Bacillus subtilis] transforming DNA with the sulphydryl (SH)-containing compound dithiothreitol (DTT) was determined using a fast response method, the gas explosion technique, to be 1.6 .times. 106 dm3 mol-1 s-. Glutathione reacts 10 times slower than DTT with the irradiated transforming DNA. Transforming DNA radicals evidently react with O2 in a damage-fixing reaction with a rate of about 3 .times. 108 dm3 mol-1 s-1. These rates are compared with values in the literature for reaction rates of SH, compounds and O2 with irradiated DNA constituents and with bacterial cells.