The mechanism for the formation of vinegar-cured, unheated surimi-gel, so called shime-kamaboko in Japan, from Alaska pollack frozen surimi was investigated. In the SDS-PAGE pattern, a band due to the myosin heavy chain disappeared after dialyzing a sol of the salted fish flesh, shio-surimi, against Walpole buffer (pH 0.5-6.5). The breaking force and deformation of shime-kamaboko were maximized at around pH 4.0, but remained constant in the pH range of 1.0-4.2 if the muscle proteins of the surimi were succinylated. These values were increased by adding salt, but decreased by adding urea or guanidine-HCl. The fluorescence intensity of shio-surimi measured in the presence of ANS-Na was scarcely affected by reducing the pH value.