Thermal denaturation and autolysis profiles of myofibrillar proteins of mantle muscle of jumbo squid Docidicus gigas

Abstract

Jumbo squid was very similar to Japanese common squid in terms of myofibrillar Ca2+‐, Mg2+‐ and K+(EDTA)‐ATPase activities. Myofibrils of jumbo squid were significantly stabilized upon addition of Ca2+ and destabilized by increasing KCl concentration for heating. Incubation of muscle homogenate of jumbo squid induced a selective cleavage of myosin into two major fragments and the cleavage was inhibited by EDTA. Autolysis was prominent at and above 0.3 M NaCl where myosin filaments dissolve. The enzyme involved in the autolysis was proved to be unstable showing maximal autolysis rate at 25°C. Washing the homogenate partially reduced the autolysis activity.

DSC and electrophoretic studies on protein denaturation of Anodonta woodiana (Lea, 1834)

“…This can indicate that myosin in the AM and F muscles can be degraded by proteolytic enzymes. Konno et al [25] also reported that myosin was the major target protein for proteinases and that the proteolytic activity remained unchanged during frozen storage.…”

Producción y evaluación funcional de un concentrado proteico de calamar gigante (Dosidicus gigas) obtenido mediante disolución alcalina Production and functional evaluation of a protein concentrate from giant squid (Dosidicus gigas) obtained by alkaline dissolution

“…Por otra parte, es bien conocido que el mu´sculo del manto de calamar (Dosidicus gigas) al igual que otras especies contiene enzimas proteolı´ticas que degradan las mole´culas de miosina en fragmentos ma´s cortos, una enzima proteolı´tica que rompe la mole´cula de miosina en fragmentos de meromiosina pesada y meromiosina ligera (MML) y otra que rompe la miosina en subfragmentos S-1 y varilla (Konno, Young-ie, Yoshioka, Shinho, & Seki, 2003). Sa´nchez et al (2007), obtuvieron un concentrado proteico a partir de manto de calamar (Dosidicus gigas) y evaluaron la autolisis de las proteı´nas en un periodo de 24 horas a 2-5 8C, observaron que la CPM decrecio´en un 93% durante las primeras 2 horas y desaparecio´completamente despue´s de 24 horas de almacenamiento.…”

Thermal gelation of myofibrillar proteins from aquatic organisms

“…The sarcoplasmic fraction contains enzymes, such as proteases, which act on myosin, producing HMM and LMM, while other enzymes cleave myosin subfragments S1 and S2. It is believed that this degradation leads to deterioration of the thermal gel (Konno, Young-Je, Yoshioka, Shinho, & Seki, 2003;Nagashima, Ebina, Nagai, Tanaka, & Taguchi, 1992). Furthermore, other myofibrillar proteins, such as actin, regulatory and cytoskeletal proteins, do not form gels.…”