Purification and partial characterization of myosin II from rat testis

The intent, in this work, was to isolate rat testis myosin II. Testis 40,000 x g x 40' supernatant was frozen at -20 degrees C for 48 h and, after it was thawed and centrifuged. The precipitate, after washed twice, was enriched in three polypeptides bands: p205, p43 and one that migrated together with the front of the gel. These polypeptides were solubilized in pH 10.8 at 27 degrees C and separated in Sephacryl S-400 column. Three low weight polypeptides co-eluted together with p205. The p205 was marked with anti-myosin II, possess actin-stimulated Mg-ATPase activity and co-sedimented with F-actin in the absence, but not in the presence, of ATP. In the present study, we have been developing a method for purification of myosin II from rat testis.