| Abstract: | Phytase (myo-inositol hexakisphosphate phosphohydrolase) has been purified about 2,000-fold from ungerminated rye with a recovery of 6%. The enzyme behaves as a monomeric protein of a molecular mass of about 67 kDa. OptimalpH for the degradation of phytate has been found at pH 6.0 and 45C. Kinetic parameters for the hydrolysis of Na-phytate are KM300 μM and kcat 358 s?1 at 35C and pH 6.0. The rye enzyme exhibits a broad affinity for various phosphorylated compounds and hydrolyses phytate in a stepwise manner; the pentakis- and tetrakisphosphate were identified as 1(1,2,3,4,5)P5 and I(2,3,4,5)P4 Consequently, this enzyme is a 6-phytase (EC 3.1.3.26). |
