[Extraction and investigation of ATPase of Tetrahymena pyriformis cilia]

The ATPase-active proteins were solubilized from T. pyriformis of cilia by treatment of the cilia with the non-ionic detergent Triton X-100. The activity of Triton-solubilized ATPase is stimulated by Ca2+ and is sensitive to EGTA. Electron microscopy has demonstrated that treatment of the cilia with Triton results in demembranation of the cilia. An electrophoretic analysis of protein composition of the cilia before and after the removal of membranes and Triton extraction has shown that dynein and tubulin, the high molecular weight proteins of ciliary axonemes, are not extracted into solution; the Triton extracts were found to contain proteins with molecular weights of 104 000, 94 000, 71 000, 62 000 and 21 000, respectively. The ATPase was purified 10-25-fold by chromatography on DEAE-Sephadex A-50. Na-DS polyacrylamide gel electrophoresis revealed that the highly purified Ca2+-ATPase of cilia consists of two subunits with molecular weights of 93 000 and 85 000. The role of Ca2-ATPase in the mechanism of motility of T. pyriformis of cilia is discussed.