title: Heterogeneity of 14S and 30S dynein ATPase activities with respect to activation by calmodulin.
abstract: Demembranated cilia of Tetrahymena pyriformis were extracted with KCl or Tris-EDTA and the crude dyneins from each resolved by sucrose density gradient sedimentation into 14S-K, 30S-K, 14S-E and 30S-E dyneins, respectively. The calmodulin activation ratio (ATPase activity in presence of added calmodulin/ATPase activity in absence of added calmodulin) did not vary across the 30S dynein fractions regardless of the method of extraction nor did it vary across the 14S-E region. However, in going from the "heavy" fractions to the "light" fractions of the 14S-K region, it increased markedly. The concentration of calmodulin required for half-maximal activation did not differ appreciably in the "light" versus the "heavy" fractions of the 14S-K region, suggesting that the affinity for calmodulin does not vary in these fractions. SDS-polyacrylamide gel electrophoresis studies showed the presence of several polypeptides that varied in a systematic fashion across the 14S-K region and hence may be involved in regulating the sensitivity of 14S-K dynein ATPase activity to added calmodulin.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000494:pharmacology*; D002147:Calmodulin / Q000494:pharmacology*; D002499:Centrifugation, Density Gradient; D002923:Cilia / Q000201:enzymology; D004398:Dyneins / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D013769:Tetrahymena pyriformis / Q000201:enzymology*
chemical_list: D002135:Calcium-Binding Proteins; D002147:Calmodulin; D000251:Adenosine Triphosphatases; D004398:Dyneins