Isolation of α-actinin from sarcoma 180 ascites cell plasma membranes and comparison with smooth muscle α-actinin

Abstract

α-Actinin from Sarcoma 180 ascites cell plasma membranes was purified after extraction in 10 mM Tris, 1 mM EDTA, 1 mM mercaptoethanol, pH 8.5, by chromatography on DEAE and hydroxyapatite for comparisons with smooth muscle α-actinin purified from turkey gizzard by the same procedure. The two proteins were found to be very similar by sedimentation analysis, gel filtration and dodecyl sulfate gel electrophoresis. Direct comparisons of smooth muscle, skeletal muscle and ascites α-actinin by amino acid analysis indicated a closer relationship between the smooth muscle and ascites proteins than between the smooth and skeletal muscle proteins. Both smooth muscle and ascites α-actinins cross-link F-actin filaments. The results suggest that the smooth muscle protein is a better system for understanding properties of nonmuscle α-actinins than is the skeletal muscle protein.