Purification and Catalytic Properties of a Phytase from Scallion (Allium fistulosum L.) Leaves

Levels of phytase comparable to that in wheat germ were detected in a variety of fresh vegetables. Scallion leaf phytase was purified 31 000-fold to an activity of 500 μmol min - 1 mg - 1 at 37 °C and had a K m of 200 μM for inositol hexakisphosphate and maximum activity at pH 5.5. The enzyme had a temperature optimum of 51 °C and was inactivated by preincubation for 10 min at 65 °C. The product specificity appeared similar to that of wheat phytase and was not altered by a 10-fold excess of magnesium. Vegetable phytases may be an alternative to seed and microbial phytases for use in the processing of food and feed products.