An ESR study of the radicals in X-irradiated L-alpha-amino-n-butyric acid HCl containing 1.5% L-cysteine HCl.

After X-irradiation at room temperature, the radicals in L-alpha-amino-n-butyric acid HCl are CH3CH2CHCOOH. The beta- and alpha-hyperfine constants are typical of those found in amino acid radicals. On annealing at temperatures near 100 degrees C this carbon-centered radical in samples containing 1.5% cysteine converts to a perthiyl radical, RCH2S(1)S(2). The g-values for the perithiyl radical are 2.0024, 2.0257, and 2.0557. When the field is in the minimum g-value direction, the hyperfine splittings are 50 G for 33S(2) and 32 G for 33S(1).