title: Dissociation of Tetrahymena 30 S dynein into 14 S subunit by sonication.
abstract: The sonication of 30 S dynein obtained from Tetrahymena cilia induced dissociation into 14-S subunits, some of the enzyme still remaining as intact 30 S dynein and partially dissociated dynein (21 S) in a minor amount. It was demonstrated that the enzymatic properties of the 14 S subunit are quite similar to those of 30 S dynein except for the Ca2+:Mg2+ ratio. ATPase (EC 3.6.1.3) (ATP phosphohydrolase activity of the 14 S subunit was steadily enhanced by increasing concentrations of Mg2+. It was also activated by Ca2+ with an optimum at 6 mM but inhibited by a further increase in concentration. The Ca2+:Mg2+ ratio at 1 mM was about 0.62. 0.6 M KCl stimulated ATPase activity of the 14 S subunit two-fold. The Mg2+-ATPase had an optimum at pH 6.2 and revealed a high activity over pH 10. The Ca2+-ATPase showed two optima at pH 6.2 and 9.5. The Km for ATP was 10 muM. Only 10% of the 14 S subunit recombined with the outer fibers in the presence of Mg2+. The 14 S subunit was shown to have the same mobility as that of 30 S dynein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002499:Centrifugation, Density Gradient; D004789:Enzyme Activation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances; D008274:Magnesium / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011485:Protein Binding; D011506:Proteins / Q000032:analysis; D013010:Sonication; D013769:Tetrahymena pyriformis / Q000032:analysis* / Q000201:enzymology
chemical_list: D046911:Macromolecular Substances; D011506:Proteins; D011189:Potassium Chloride; D000251:Adenosine Triphosphatases; D008274:Magnesium; D002118:Calcium