Purification of endogenous transglutaminase from daggertooth pike conger fish (Muraenesox cinerus) meat

Abstract

Daggertooth pike conger fish (Muraenesox cinerus) has the potential to be used as a raw material for the surimi industry because it has high yield and white flesh. Surimi quality is not only influenced by the production process but also by the strength of the texture which is in turn influenced by the transglutaminase enzyme (TGase) in the fish meat. However, the activity and characteristics of TGase in the fish meat were not clearly known. The present work, therefore, aimed to characterise the TGase in daggertooth pike conger fish meat. Results showed that the crude extract of TGase had an activity of 0.240 U/mL, and increased following dialysis (0.823 U mL); in other words, the activity underwent purity boosting as much as 1.983 times. Moreover, TGase in daggertooth pike conger fish meat was found to have an optimum temperature of 40 - 50°C and pH 8, with a molecular size of around 80 kDa. It was also found that the reactivity of TGase depended on Ca2+ ions and could be increased with Mg2+ ions, but could be inhibited by Fe2+ ions.