Search

Chymotrypsin was purified from jumbo squid hepatopancreas (HP) with 2.4-fold and yield 1.9%, and characterized with a molecular weight of 31 kDa, as estimated by sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE). Chymotrypsin effect over collagen extracted from the mantle, fins and arms of the jumbo squid was evaluated. The enzyme exhibited the maximum activity at pH 7 and 65°C using Suc-Ala-Ala-Pro-Phe-p-nitroanilide (SAAPNA) as a substrate and it was identified using the specific inhibitors N-tosyl-L-phenylalaninechloromethyl ketone (TPCK) and phenyl methyl sulfonyl fluoride (PMSF), showing residual activities of 6% and 0%, respectively. Furthermore, high activity was observed in the pH range of 4.0 to 8.0. Purified enzyme showed a moderate in vitro activity using muscle collagen as a substrate. Although further research is needed, the results suggest that the enzyme has a potential application where acidic or slightly alkaline conditions are needed.

Myofibrillar protein are the principally responsible of gelling properties in fishery resource, hence, during protein concentrate or isolated proteins preparation, sarcoplasmic protein are discarded; however, myofibrillar protein can support low levels of sarcoplasmic proteins without affecting the gelling property. Therefore, the aim of this study was to gradually remove sarcoplasmic proteins from giant squid mantle by means of different ionic strengths (I). Solutions of NaCl with different ionic strengths (I=0.0, 0.1, and 0.3) were used to obtain 3 protein concentrates. The electrophoretic profile in SDS-PAGE showed differences in protein removal with a high solubility of mantle proteins. The texture profile analysis showed that hardness increased in mantle protein washed with higher I. The total reactive sulfhydryls showed significant changes (p