Biopolymers and cell. 1998; 14 (1): 19 - 22

Supramolecular species of smooth muscle myosin light chain kinase. 2. Kinetics of mutual transitions

A. M. Filenko, V. M. Danilova, A. Sobieszek

In a previous work we have shown using tight scattering methods that myosin light chain kinase (MLCK.) exists in solution as an equilibrium mixture of oligomeric, dimeric and monomeric species, which relative concentrations at physiological ionic strength cons¬titute correspondingly 2, 53 and 45 weight percent. During myosin phosphorylation in vivo the relationship between these kinase species which are possibly different by their activity may significantly change causing the necessity of perceiving time dependent charac¬teristics of the transition between them. To perform the last we used the fact that gel filtration and CaM-affinity columns largely shift the equilibrium towards supramolecular MLCK species. Therefore, by interrupting the elution in the points where the only species was prevailing we could make for this species an estimate of transition time into the equilibrium state. Data obtained have shown that the kinase oligomer, dimer and monomer were rather stable structures so that the mutual transition between them when approaching to the equilibrium took time up to 10 min.