Effects of l-arginine and l-histidine on heat-induced aggregation of fish myosin: Bighead carp (Aristichthys nobilis)

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.