摘要
以夏威环毛蚓（Ｐｈｅｒｅｔｉｍａ ｈａｗａｙａｎａ）为材料，采用磷酸盐缓冲液抽提、（ＮＨ４）２ＳＯ４分段盐析，离子交换树脂 Ｄ２９０、 Ｓｅｐｈａｄｅｘ Ｇ－１００和 ＤＥＡＥ－ｓｅｐｈａｄｅｘ Ａ－５０三种连续柱层析方法得到一种在 ＰＡＧＥ上显示单一区带的纤溶酶组份。采用凝胶柱层析和 ＳＤＳ－ＰＡＧＥ测其分子量为 １２ ０００和 １２３００，由一条肽链组成。该酶具有强烈的纤溶活力和水解ＢＡＥＥ的活力，能直接作用纤维蛋白和间接激活纤溶酶原。其最适反应温度为４５℃，最适反应ｐＨ为８．０。该酶水解ＢＡＥＥ的活力可被Ｎａ＋、Ｋ＋、Ｍｇ２＋、Ｈｇ２＋、金属离子和ＥＤＴＡ、巯基乙醇抑制，Ｃａ＋则有激活作用。该酶中性糖含量为５％，氨基酸组成中Ａｒｇ、Ｌｅｎ含量较多．
Grude plasmin from Pheretima hawayana was extracted from earthworm tissue and precipitated with (NH4 )2So4. Using column chromatography of ion-exchange resin D290, sephadex G-100 and DEAE-sephadex A-50, the enzyme was purified, showing only one protein band on PAGE (pH 8. 3). The enzyme contains no subunit, and its molecular weight is 12300 and 12000 by SDS-PAGE and sephadex G-100 gel filtration respectively. The enzyme showed strong fibrinolytic activity on fibrin and esterase activity in BAEE. It shows two effects, both acting on fibrin directly and activating plasminogen. Its optimum temperature is 45℃, optimum pH 8. 0. The enzyme activity is stable within PH range from 5 to 9. 6 for 1 hour at 37℃. Na+,K+,Mg2+,Hg2+, EDTA and mercaptoethanol show some inhibition with various degrees. Ca2+can increase its activity. The enzyme contains 5 percent neutral sugar. Amino acid analyses show high levels of Arg and Leu.
出处
《动物学报》
SCIE
CAS
CSCD
1996年第2期146-153,共8页
ACTA ZOOLOGICA SINICA
