The Radiolysis of Dilute Solutions of Lysozyme

Summary

Pulse radiolysis was used for the study of transients formed from lysozyme solutions. Reactions of these transients with cysteine and oxygen were analysed kinetically. The rate constant for the reaction of lysozyme with e⁻_aq was 5·2 × 10¹⁰ M⁻¹ sec⁻¹ and for lysozyme with OH was 3·1 × 10¹⁰ M⁻¹ sec⁻¹. For the reaction of the lysozyme transient (λ_max 400 mμ) with cysteine and oxygen, the rate constants were 4·1 × 10⁶ M⁻¹ sec⁻¹ and 3·38 × 10⁸ M⁻¹ sec⁻¹ respectively. The corresponding figures for the lysozyme transient (λ_max 310 mμ) were 4·6 × 10⁸ M⁻¹ sec⁻¹ and 1·6 × 10⁸ M⁻¹ sec⁻¹. These data are correlated with those obtained from steady-state radiolysis and elucidate an aspect of the known radiobiological oxygen effect.