Hogan S P, Foster P S, Hansbro P M, Ozaki S, Denborough M A
Division of Biochemistry and Molecular Biology, John Curtin School of Medical Research, Australian National University, Canberra.
Cell Signal. 1994 Feb;6(2):233-43. doi: 10.1016/0898-6568(94)90081-7.
A myoplasmic 3-kinase was detected in porcine skeletal muscle that phosphorylated [3H]Ins(1,4,5)P3 [D-myo-inositol(1,4,5)trisphosphate] to [3H]Ins(1,3,4,5)P4 [D-myo-inositol(1,3,4,5)tetrakisphosphate]. The Ins(1,4,5)P3 3-kinase activity was ATP- and Mg(2+)-dependent, and was activated by Ca2+ and calmodulin. Ins(1,4,5)P3 3-kinase activity was purified 2632-fold from soluble extracts of skeletal muscle by a combination of DEAE-Sephacel, heparin-Agarose and Ins(1,4,5)P3 structural-analogue affinity chromatography. The highest specific activity obtained was 10.6 nmol of Ins(1,4,5)P3 phosphorylated/min/mg protein. The partially purified enzyme had a mean Km and Vmax of 0.46 microM and 3.15 nmol/min/mg protein for Ins(1,4,5)P3 metabolism, respectively. After analytical gel filtration two forms of soluble Ins(1,4,5)P3 3-kinase were observed with M(r) of 39,000 and 62,000. As in other cell types, muscle Ins(1,4,5)P3 3-kinase was soluble, and had a higher affinity but a lower capacity to metabolize Ins(1,4,5)P3 in comparison to Ins(1,4,5)P3 5-phosphatase.
在猪骨骼肌中检测到一种肌质3-激酶，它可将[3H]Ins(1,4,5)P3[D-肌醇(1,4,5)三磷酸]磷酸化为[3H]Ins(1,3,4,5)P4[D-肌醇(1,3,4,5)四磷酸]。Ins(1,4,5)P3 3-激酶活性依赖于ATP和Mg(2+)，并被Ca2+和钙调蛋白激活。通过DEAE-琼脂糖凝胶、肝素-琼脂糖和Ins(1,4,5)P3结构类似物亲和色谱相结合的方法，从骨骼肌可溶性提取物中纯化出Ins(1,4,5)P3 3-激酶活性2632倍。获得的最高比活性为10.6 nmol Ins(1,4,5)P3磷酸化/分钟/毫克蛋白。部分纯化的酶对Ins(1,4,5)P3代谢的平均Km和Vmax分别为0.46 microM和3.15 nmol/分钟/毫克蛋白。经过分析性凝胶过滤后，观察到两种可溶性Ins(1,4,5)P3 3-激酶形式，其分子量分别为39,000和62,000。与其他细胞类型一样，肌肉Ins(1,4,5)P3 3-激酶是可溶的，与Ins(1,4,5)P3 5-磷酸酶相比，它对Ins(1,4,5)P3代谢具有更高的亲和力，但代谢能力较低。
