Determination of the binding constant of a protein kinase C substrate, NG(28-43), to sodium dodecyl sulfate via the diffusion coefficient measured by pulsed field gradient nuclear magnetic resonance.

The binding affinity of a protein kinase C substrate, neurogranin peptide NG(28-43), to a sodium dodecyl sulfate micelle was analyzed quantitatively by the diffusion coefficient (Da) of the peptide determined by pulsed field gradient NMR. By use of a two-state model, the fraction of the peptide in the bound state, and hence the binding constant, can be estimated. The obtained binding constant is within the same order of magnitude as those reported for similar systems using other techniques. The present method may be generalized to measure the formation constants of other peptide:micelle complexes.