title: Double and single exponential kinetics of microtubule assembly in vitro.
abstract: The kinetics of the microtubule protein assembly were studied in Mes buffer, pH 6.6, at 28 degrees C. The assembly under above conditions follow a kinetic expression containing two exponential terms. The observed two rate constants depend on protein concentration, and are on the order of 10(-2) sec-1 and 10(-3) sec-1. When CaCl2 is added to the system in low concentration, the kinetic expression becomes single exponential. The observed rate constant is independent of protein concentration and its value is 5 X 10(-3) sec-1. It is concluded that the double exponential kinetics correspond to favorable assembly conditions, probably to a high extent of nucleation, whereas the single exponential kinetics correspond to favorable assembly conditions, probably to a high extent of nucleation, whereas the single exponential kinetics is a slower process which occur under hindered assembly conditions.
mesh_terms: D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D002122:Calcium Chloride / Q000494:pharmacology; D002417:Cattle; D066298:In Vitro Techniques; D007700:Kinetics; D008868:Microtubule Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological
chemical_list: D008868:Microtubule Proteins; D002122:Calcium Chloride