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ABSTRACT

Four soluble phytases were identified in germinating spelt. Although numerous purification strategies were applied, none of the four phytases could be purified to homogeneity. The purest phytase preparation, called D21, contained a phytase (major component) and an acid phosphatase (APH) (minor component). The phytase behaves like a monomeric protein of a molecular mass of about 68 kDa and shows a broad substrate specificity. Optimal pH for degradation of phytate was 6.0 and the optimal temperature 45C. Kinetic parameters for the hydrolysis of Na-phytate were KM 400 μmoll−1 and kcat 368s−1 at pH 6.0. The spelt phytase D21 degrades phytate stepwise.