多头绒泡菌肌球蛋白的纯化及性质的研究

从多头绒泡菌中纯化了肌球蛋白，并对其亚基组成及ＡＴＰ酶性质进行了研究。该肌球蛋白是由一种重链（２２５ｋＤ）和两种轻链（２０ｋＤ，１７．５ｋＤ）组成的大分子，其亚基之比为ＨＣ：ＬＣ１：ＬＣ２＝２：４：２。兔肌Ｆ－肌动蛋白能较大激活粘菌肌球蛋白ＡＴＰ酶活性，Ｃａ~（２＋）离子也能提高其活性，Ｍｇ~（２＋）离子无明显影响。钒酸盐，碘乙酸，对氯汞苯甲酸对其ＡＴＰ酶活性有显著抑制作用。

Purification and Characterization of Myosin from Physarum polycephalum

Myosin was purified from Physarum polycephalum and its subunit component and ATPase properties were studied. The plasmodium actomyosin was precipitated and polymerized repeatedly. After depolymerization of the purified actomyosin,the plasmodium myosin was chromatographed by Sepharose 4B gel filtration.The results proved that plasmodium myosin is comprised of one kind of heavy chain and two kinds of light chains. The subunit composition of plasmodium myosin is HC:LC_1: LC_2= 2:4:2.The activity of plasmodium myosin ATPase can be activated by the F-actin of rabbit muscle.The activity of plasmodium myosin can be activated by Ca￣(2+) ions,but not by Mg￣(2+)ions. The activity of plasmodium myosin is inhibited by p-chloromercuribenzoate (PCMP)and iodoacetate.It show that thiol group and tyrosine may located on the active site of plasmodium myosin.