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KMID : 0578319930030010095
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Molecules and Cells
1993 Volume.3 No. 1 p.95 ~ p.99
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Purification and Properties of myo-Inositol Monophosphate Phosphatase from Porcine Brain
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Kwon, Hyeok
Shin, Hyung Cheul/Lee, Yun Lyul/Park, Hyoung Jin/Cho, Sung Woo/Choi, Soo Young
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Abstract
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Inositol monophosphatc phosphatase is a key enzyme in the phosphoinositide cell-signaling system. An inosital monophosphate phosphatase has been purified from porcine brain in ammonium sulfate fractionation, Q-Sepharose, Sephacryl S-200, Mono-Q, Mono-S and Phenyl-Superose chromatographic steps. The purified enzyme appeared homogeneous on denatured SDS-polyacrylamide gel electrophoresis and its molecular mass was estimated to be 43 kDa. The molecular mass of the native enzyme was 67 kDa. as determined by gel-filtration and native gradient polyacrylamide gel electrophoresis. The Km for natural substrate, myo-Inositol-l-phosphate was 0.57 mM whereas the Km for Q-glycerophosphate was 4.17 mM. The enzyme shows an optimum pH at 7.4 and has an absolute requirement of Mgt+. The enzyme, however, was inactivated in the presence of other divalent cations such as Mn", Ca´-1, Fe 21, CU2´ and Zn´-+. Lithium ion also acts as a strong inhibitor of the enzyme.
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