Abstract
The inhibitory activity of various proteins such as, pepsin, α-casein, whole casein, egg albumin, β-lactoglobulin, gelatin, human serum fibrinogen, upon the oxidation of ascorbic acid was examined by the rate of oxygen consumption with the aid of Warburg manometer. The sequence of them by copper ion is as follows : Pepsin<α-casein<whole casein>egg albumin>β-lactoglobulin. This effect of these proteins decreases when the prothins are denatured by heat. The highest inhibitory activity is observed when the protein whose isoelectric point is approximately 4.6 is used and this activity decreases when the protein whose isoelectric point is either higher or lower than 4.6 is used. The same effect of proteins was observed in the enzymatic oxidation of ascorbic acid by ascorbic acid oxidase.
