Iwasa F, Ishiguro K
J Biochem. 1986 May;99(5):1353-8. doi: 10.1093/oxfordjournals.jbchem.a135603.
A calmodulin-binding protein from sea urchin eggs consisting of two subunits (55 and 17K-daltons) was identified as a Ca2+-dependent phosphoprotein phosphatase similar to calcineurin in mammalian brain and to phosphatase 2B in skeletal muscle. Peptide mappings showed that the 55K subunit was different from 61K subunit of calcineurin, whereas the 17K subunit was similar to 19K subunit of calcineurin but different from calmodulin. The 55K + 17K protein of sea urchin eggs dephosphorylated 32P-inhibitor-1 in a Ca2+- and calmodulin-dependent manner. Vmax and Km for inhibitor-1 in the presence of Ca2+ and calmodulin were 2,100 pmol Pi/min/mg and 2.7 microM. Ca2+-dependent phosphatase activity for inhibitor-1 was detected in homogenates of both unfertilized and fertilized eggs, but was not detected in isolated cortices and mitotic apparatus.
从海胆卵中鉴定出一种钙调蛋白结合蛋白，它由两个亚基（55千道尔顿和17千道尔顿）组成，是一种钙依赖性磷蛋白磷酸酶，类似于哺乳动物脑中的钙调神经磷酸酶和骨骼肌中的磷酸酶2B。肽图谱显示，55K亚基与钙调神经磷酸酶的61K亚基不同，而17K亚基与钙调神经磷酸酶的19K亚基相似，但与钙调蛋白不同。海胆卵的55K + 17K蛋白以钙和钙调蛋白依赖性方式使32P-抑制剂-1去磷酸化。在存在钙和钙调蛋白的情况下，抑制剂-1的Vmax和Km分别为2100皮摩尔无机磷/分钟/毫克和2.7微摩尔。在未受精卵和受精卵的匀浆中均检测到抑制剂-1的钙依赖性磷酸酶活性，但在分离的皮质和有丝分裂装置中未检测到。
