Abstract
The present paper reports the influence of metallic ions on the inhibition of α-amylase activity by riboflavin in the light condition. The inhibiting action of riboflavin to the α-amylase activity under the light condition is to some extent decreased by Ca^<2+> and Sr^<2+>, whereas the subsequent activity of α-amylase, after the inhibition of riboflavin, is not activated by the addition of Ca^<2+> and Sr^<2+> in the riboflavin solution. At that time lumichrome is formed by the effect of light. It appears that the combination of Ca^<2+> to enzyme protein is weaker than that of riboflavin to enzyme protein. It may be concluded that the inhibiting action of riboflavin on the α-amylase activity is due to the combination of riboflavin to enzyme protein and to the photooxidation of modified enzyme protein induced by riboflavin.
