Purification and properties of myo-inositol-1-phosphatase from rat brain.
Purification and properties of myo-inositol-1-phosphatase from rat brain.
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大鼠脑肌醇-1-磷酸酶的纯化和性质。
DOI：
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发表时间：
1985
期刊：
影响因子：
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通讯作者：
H. Nakagawa
中科院分区：
文献类型：
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作者：
K. Takimoto;M. Okada;Y. Matsuda;H. Nakagawa
从大鼠脑的胞质部分纯化肌-肌醇-1-磷酸酶[EC 3.1.3.25]。纯化的酶在SDS-聚丙烯酰胺凝胶电泳上呈现均一性，其分子量估计为29，000。通过分子筛色谱法测定，天然酶的分子量为55，000。这些值表明天然酶由两个相同的亚基组成。该酶的等电点为4.6。该酶水解肌醇-1-磷酸、2 '-AMP、2'-GMP、β-甘油磷酸和α-甘油磷酸;反应速率比为100：84：73：64：32。肌醇-1-磷酸、2 '-AMP和β-甘油磷酸的Km值分别为1.2 × 10（-4）M、1.9 × 10（-4）M和7.7 × 10（-4）M。Mn 2+和Ca 2+是Mg 2+的强竞争性抑制剂，Ki值分别为3 μ M和20 μ M。这一结果表明，肌醇-1-磷酸酶可能受到细胞内Ca ~（2+）和/或Mn ~（2+）的调节。Li+，这是已知的躁狂抑郁症的治疗效果，也延长了固有的周期的昼夜节律在各种生物体，是一种有效的非竞争性抑制剂，并抑制50%的活性在1毫米。的可能性，肌醇-1-磷酸酶和肌醇磷脂代谢参与昼夜节律振荡进行了讨论，在锂行动。
myo-Inositol-1-phosphatase [EC 3.1.3.25] was purified from a cytosolic fraction of rat brain. The purified enzyme appeared homogeneous on SDS-polyacrylamide gel electrophoresis and its molecular weight was estimated to be 29,000. The molecular weight of the native enzyme was 55,000 as determined by molecular sieve chromatography. These values indicated that the native enzyme was composed of two identical subunits. The isoelectric point of the enzyme was 4.6. The enzyme hydrolyzed inositol-1-phosphate, 2'-AMP, 2'-GMP, beta-glycerophosphate, and alpha-glycerophosphate; the ratio of the reaction rates was 100 : 84 : 73 : 64 : 32. The Km values for inositol-1-phosphate, 2'-AMP, and beta-glycerophosphate were 1.2 X 10(-4) M, 1.9 X 10(-4) M, and 7.7 X 10(-4) M, respectively. Mn2+ and Ca2+ were strong competitive inhibitors against Mg2+, with Ki values of 3 microM and 20 microM, respectively. This result suggests that myo-inositol-1-phosphatase might be regulated by intracellular Ca2+ and/or Mn2+. Li+, which is known to show a therapeutic effect on manic-depressive disease and also to prolong the intrinsic periods of circadian rhythms in various organisms, was a potent uncompetitive inhibitor and inhibited 50% of the activity at 1 mM. The possibility that myo-inositol-1-phosphatase and inositol phospholipid metabolism are involved in circadian rhythm oscillation is discussed in terms of Li actions.