Purification and properties of a nonspecific acid phosphatase from wheat germ.

While studying the phosphoglyceric acid mutase of wheat germ, we noted marked phosphatase activity when extensively purified mutase preparations were tested with n-3-phosphoglyceric acid and D-Z, 3diphosphoglyceric acid as substrates (1). Since we had found low phosphatase activity for these reagents in many biological materials (2), there was the possibility, previously discussed (l), that the enzymatic hydrolysis of these substrates was a dual function of the purified wheat germ mutase. Further examination, however, showed there was no correlation between phosphatase and mutase activities at several stages of purification, indicating phosphatase contamination of the wheat germ mutase preparations. Additional evidence for the nonidentity of the two enzymatic activities has now been obtained by extensive purification of the phosphatase from wheat germ, by the method presented in this paper. The purified preparations of nonspecific acid phosphatase described in this paper have activities of the same order of magnitude as those of the extensively purified intestinal monoesterase (3) and of the crystalline pyrophosphatase of yeast (4). The best phosphatase preparations are essentially free of P-glycerate mutase activity.