• Journal of Life Science
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• v.7 no.2
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• pp.119-126
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• 1997

Phytase(myo-inositol hexkisphosphate phosphohydrolase ; EC 3.1.3.8) was purified from the mucoas of rat intestinal. The molecular weight of enzyme was determined to be 160kDa by sephacryl S-200 gel filtration. Analysis of the purified enzyme o SDS-polyacrylamide gel electrophoresis(SDS-PAGE) showen that it was composed of two different subunits and the molecular weight of its subunit was found to be 70kDa and 90kDa respectively, indicating that this enzyme is hetrodimer. The enzyme activities were activated in the presence of $ MgCl_{2}$, but inhibited by $ZnCl_{2}$, $MnCl_{2}$, and EDTA. The substrates tested, phytase showed the highest affinity for the enzyme at the physiological ph. The Km value for phytic acid(inositol-hexakisphosphate)was 0.31 mM at pH 7.4. rat intestinal mucosa phytase seems to play an important in the metabolism of inositol.

• Journal of Life Science
• /
• v.7 no.2
• /
• pp.127-133
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• 1997

The phytase(myo-inositol hexkisphosphate phosphohydrolase ; EC 3.1.3.8) activity was observed only in the homogenate of intestinal mucosa, though the activity of alkaline phisphatase was measurable in various organs. In addition, no protein bands were detected in any other organs on immunoblotting using the anti-90kDa phytase antiserum. Thses results suggest that phytase is specifically present in small intestinal mucosa, and that hydrolysis of phytic acid(inositol-hexakisphosphate) can be allotted for a physiological role of the intestine-specific enzyme. The activities of phytase was increased during development of rat. The 70kDa phytase appeared just after birth, but the 90kDa phytase was not observed until adult period, suggesting that the 90kDa phytase was synthesized in response to weanling.