CHARACTERIZATION OF PROTEOLYTIC ACTIVITY IN OCTOPUS (Octopus vulgaris) ARM MUSCLE

Abstract

A new proteolytic activity assay was devised to avoid the interference of paramyosin which causes gelling during the enzymatic assay. Extremely high autolytic activity was observed in octopus arm muscle, which was 40–500 fold higher than those of various other fish species. The proteinase was inhibited strongly by leupeptin and iodoacetic acid and, to a lesser degree, by transepoxysuccinyl‐L‐leucylamino (4‐guanidono)butane (E‐64), indicating the class as a thioi proteinase. The proteinase exhibited optimum activity at pH 2.5 and 40C, although it contained a sulfhydryl group in the active site. Myosin heavy chain was the primary myofibrillar protein which was hydrolyzed during the autolysis of octopus arm followed by paramyosin. Actin showed no signs of hydrolysis during the incubation of up to 8 h. Due to its high affinity for myosin, the enzyme activity should be controlled during processing octopus to ensure the functionality of myosin.

Proteolytic Activity in Actomyosinfrom Mantle and Fin of Squid (Illexargentinus) Stored at 2-4°C. Influence on the Physicochemical and Functional Properties of the Protein

“…Previous works have informed on the physico-chemical, biochemical, and functional properties of major myofibrillar proteins from squid Illexargentinus (Paredi, Roldán, & Crupkin, 2006;Mignino & Paredi, 2006). It had been also reported that, cephalopods have peculiarities of proteins and high level of proteolytic activity, higher than that of most fish species (Hurtado, Borderías, Montero, & An, 1999). Moreover, it has been reported that some of the proteases involved in that proteolytic activity, have as target the myosin heavy chain (MHC) producing degradation of the same (Konno & Fukazawa, 1993;Konno, Yuong-Je, Yoshioka, Shinhho, & Seki, 2003).…”

Sensory, biochemical and bacteriological properties of octopus (Cistopus indicus) stored in ice

“…The endogenous proteases play an important role in softening of cephalopod tissue, including octopus (Hurtado et al 1999;Hatate et al 2000). The cornea was initially tranluscent which became slightly opalescent on day 2 and completely opalescent from day 5 onwards.…”

“…This result clearly demonstrated that the spoilage of octopus was mainly autolytic and not microbial. Hurtado et al (1999) also stated autolysis was more intense in octopus than microbial action. The total aerobic plate count at the point of rejection of fish products is usually log 7-9 CFU/g (Huss et al 1997;Olafsdottir et al 1997) and such higher counts were not obtained even on the day of rejection in the iced octopus.…”

“…Protease plays an important role in the breakdown of protein and its activity is higher than in various species of fish (Hurtado et al 1999). The major quality indices used to assess freshness or spoilage of fish viz K value, TVBN, pH and polyamines (except agmatine) are not suitable quality indices for cephalopods as some of the pathways of formation of spoilage products are different (Ohashi et al 1991).…”

Molluscs and echinoderms aquaculture: biological aspects, current status, technical progress and future perspectives for the most promising species in Italy

“…Hurtado et al (1999) reported a shelf life lasting 6 to 7 days after catch at 2.5°C and Barbosa and Vaz-Pires (2003) found a shelf life of 10 days at 0°C. Different methods and different parameters have been tested for monitoring quality and quality evolution during the shelf life, based on physical, chemical, and microbiological analysis.…”