抄録
Adenine remarkably accelerates the riboflavin-sensitized photoinactivation of sweet potato β-amylase [EC 3. 2.1. 2], but guanine has no effect. Studies on the photooxidation of native and alkali-denatured amylases and free amino acids with riboflavin in the presence and absence of adenine show that the oxidation of cysteine and methionine are accelerated by the addition of adenine, regardless of whether they are contained in the enzyme molecule or present free, and that some tryptophan residues in β-amylase are susceptible to the photooxidation and their degradations are accelerated by the addition of adenine probably because of their specific configurations in the enzyme molecule. The data also suggest that, at the photoinactivation of native β-amylase, the degradation of susceptible tryptophans are accelerated first by addition of adenine before the degradation of other amino acids, indicating their importance for the enzymatic activity.
