In vitro proteolysis of myofibrillar and sarcoplasmic proteins of European sea bass (Dicentrarchus Labrax L) by an endogenous m‐calpain

Abstract

The effects of m-calpain isolated from the skeletal muscle of sea bass on sarcoplasmic and myofibrillar proteins isolated from the same tissue were examined in vitro. Incubation of sarcoplasmic proteins with m-calpain resulted in only a slight decrease (0.7 kDa) in the molecular weight (MW) of a 26.5 kDa protein. Degradation of myofibrils, monitored by quantification of TCA-soluble peptides generated, resulted in the maximum amount of peptides being generated after 1 h of incubation at 25°C. Noticeable modifications in the SDS-PAGE profile of digested myofibrils were observed, including partial denaturation of myosin heavy chain and the release of tropomyosin, $69 and $27 kDa doublet bands and a few polypeptides of MW lower than 20 kDa in the soluble fraction. Examination of the degradation patterns of myofibrillar proteins using Western blotting showed that a-actinin was partially degraded, with release of native a-actinin and its fragments from myofibrils, whereas desmin was highly degraded after 2 h of digestion.

Identification of calpastatin, μ-calpain and m-calpain in Atlantic salmon (Salmo salar L.) muscle

“…Salmon l-calpain had already a loss of activity at 25°C and maximum activity was observed at 15°C. These results are in accordance with other studies on fish Salem et al, 2004a;Verrez-Bagnis, Ladrat, Noelle, & Fleurence, 2002), although the explanation for this difference in temperature optimum is not known.…”

Pre-rigor filleting and drip loss from fillets of farmed Atlantic cod (Gadus morhua L.)

“…Limited knowledge is available about the mechanisms behind the development of drip loss in meat, but it has been hypothesized that protein linkages within the muscle cell are of importance and that the calpain system plays a major role in PM proteolysis (Huff‐Lonergan & Lonergan 2005; Geesink, Kuchay, Chishti & Koohmaraie 2006). Far less is known about the role of the calpain system in fish muscle (Toyohara & Makinodan 1989; Geesink, Morton, Kent & Bickerstaffe 2000; Verrez‐Bagnis, Ladrat, Noëlle & Fleurence 2002; Saito, Li, Thompson, Kunisaki & Goll 2007). Other proteolytic enzymes such as cathepsins B, L and D (Yamashita & Konagaya 1990; Aoki & Ueno 1997; Ho, Chen & Jiang 2000; Ladrat, Verrez‐Bagnis, Noel & Fleurence 2003; Cheret, Delbarre‐Ladrat, de Lamballerie‐Anton & Verrez‐Bagnis 2007) and connective tissue degrading enzymes, such as matrix‐metalloproteinases (MMPs) (Bracho & Haard 1995; Saito, Sato, Kunisaki & Kimura 2000; Delbarre‐Ladrat, Cheret, Taylor & Verrez‐Bagnis 2006; Olsson, Cooper, Friis & Olsen 2006), have also been implicated in the PM degradation process of fish muscle.…”

Proteolysis and Its Control Using Protease Inhibitors in Fish and Fish Products: A Review

“…However, they are known to increase the susceptibility of other proteases to degrade the myofibrillar proteins. μ‐Calpain has a limited effect on sarcoplasmic proteins from skeletal muscle of sea bass, as indicated by a slight decrease in protein with an MW of 26.5 kDa (Verrez‐Bagnis, Ladrat, Noëlle, & Fleurence, ). Taylor et al.…”