A viscometric and electrophoretic study of the deformation and flow properties of R-actomyosin induced by adenosinetriphosphate and other adenine nucleotides 1

Abstract

A viscometric and electrophoretic study of the deformation and flow properties of R-actomyosin induced by adenosinetriphosphate and other adenine nucleotides. The deformation and flow changes induced in R-actomyosin by adenine nucleotides have been studied by electrophoresis and viscometric methods under identical experimental conditions of ionic strength, pH, temperature, protein and nucleotide concentration. The data show that a concentration of nucleotide which produces a maximal decrement of the reduced viscosity of an R-actomyosin solution does not effect a change in the electrophoretic pattern from a single component to a multicomponent system. Greater concentrations of nucleotide, however, while effecting the same viscosity change as the smaller concentrations, do produce electrophoresis patterns with 3, 4 or more components. The intrinsic viscosity value of R-actomyosin in the presence of ATP is significantly reduced from its value in the absence of ATP. This implies a reduction in the size and/or shape of this macromolecular entity. The results obtained, not only with ATP, but also with ADP, AMP and ITP, cannot be interpreted in concert with the classical concept of a dissociation of actomyosin into simply F-actin and myosin A.