Effect of l-histidine on the heat-induced aggregation of bighead carp (Aristichthys nobilis) myosin in low/high ionic strength solution

Abstract

In this study, the effects of l-histidine (L-His) on the aggregation of bighead carp (Aristichthys nobilis) myosin induced by heating in low (0.1) or high (0.5) ionic strength solutions were studied. The solubility of natural myosin was significantly enhanced by L-His both in low and high ionic strength solutions. More small particles are suspended in the heated solution containing L-His, inducing a higher solubility than that solution without L-His. The surface hydrophobicity of myosin in a low ionic strength solution containing L-His is higher than that of myosin without L-His. The results of morphology show that L-His induced myosin to form finer aggregates and a honeycomb-like network in a low/high ionic strength solution during heat treatment. These results demonstrate that L-His might disrupt the electrostatic property of unfolded myosin heat-induced through electrostatic binding with the exposed negatively charged amino acid residues, which might disarrange hydrophobic surfaces, resulting in weakening hydrophobic interactions, which ultimately suppresses the fierce aggregation of carp myosin.