Abstract
The rate constant for strand breakage in poly(U) after reaction with H atoms in deoxygenated aqueous solution was determined to be k = 1.5 s-1 at pH = 4-5 and 24.degree. C. Dithiothreitol prevents strand break formation by reacting with H-adduct radicals of poly(U) with a rate constant of 5 .times. 106 M-1 s-1. The rate-determining step in H atom-induced strand breakage in poly(U) at pH .ltoreq. 6 is the decay of uracil moiety H-adduct radicals via H-abstraction from the ribose moiety.