This research focused on the effects of l-arginine (l-Arg) and l-histidine (l-His) on the heat-induced aggregation of fish myosin. l-Arg/l-His increased the pH of the myosin solution from 6.82 to 8.74 and 7.24, respectively, and decreased the turbidity, aggregate size, shear modulus, and breaking force. The incorporation of l-Arg/l-His decreased the surface hydrophobicity during setting, but increased it during the two-step heating. The heat-induced aggregation of myosin was suppressed by both amino acids, with the inhibitory effect being greater for l-Arg than l-His. On one hand, the change in the pH played a critical role in suppressing the heat-induced aggregation of myosin. On the other hand, the characteristics of l-Arg/l-His themselves, such as net charges and particular R-groups, were another main contributor to aggregation suppression. Particularly, l-Arg/l-His could interact with exposed aromatic residues of myosin, and the interactions may dominate and overwhelm the burial of aromatic residues during two-step heating.
Keywords: Heat-induced aggregation; Myosin; Suppression; Surface hydrophobicity; l-Arginine; l-Histidine; pH.
Copyright © 2019 Elsevier Ltd. All rights reserved.