Participation of cathepsin L into extensive softening of the muscle of chum salmon caught during spawning migration.

Abstract

brillar fragments in the homogenate of the muscle having the highest autolytic activity, it was shown that 160kD and 150kD proteins gradually appeared and myosin light chains disappeared during incubation at 15•Ž and pH 6.5. This degradation pattern was similar to that of muscles having the highest autolytic activity which were stored.

Effect of harvesting stress and storage conditions on protein degradation in fillets of farmed gilthead seabream (Sparus aurata): A differential scanning calorimetry study

“…It is likely that during the thawing process the fillets experienced some degree of shrinkage and drip loss due to thaw rigor (Cappeln & Jessen, 2001), leading to the higher liquid loss observed. Yamashita and Konagaya (1990) have shown that cathepsin L is responsible for post-mortem tenderization and for the acceleration of muscle degradation during frozen storage in chum salmon (Oncorhynchus keta), possibly caused by the release of the enzyme as a consequence of the disruption of the lysosomal membrane, due to the formation of ice-crystals during freezing. In the present study, however, measured activity of cathepsin L was very low and widely variable, and cannot be clearly associated with the experimental conditions, suggesting that this enzyme has only a minor role in post-mortem proteolysis of seabream muscle.…”

Participation of cysteine protease cathepsin L in the gel disintegration of red bulleye (Priacanthus macracanthus) surimi gel paste

“…7,8 On the other hand, lysosomal cathepsin L is well known to participate in the muscle softening of chum salmon during spawning migration. 9 A cysteine protease was reported to contribute to the muscle softening of arrowtooth flounder. 10 Cathepsin L could not be removed from the surimi and degraded MHC in Pacific whiting.…”

Detection of cathepsin L in red cell membranes from fish blood

“…In chum salmon, a complex form of cathepsin L (50 kDa) is composed of two forms of cathepsin L and an endogenous inhibitor [21]. A latent form of cathepsin L with a higher molecular weight (69 kDa) also exists in lysosomes of mackerel muscle [16]. In human red cell membranes, two forms of cathepsin E with higher molecular weights (79 and 41 kDa) have been reported [22].…”

“…It is known that the protease hydrolyzes collagen is active under weak acidic conditions, and both chum salmon cathepsin L and rat liver cathepsin L do hydrolyze collagen [14,15]. Lysosomal cathepsin L is also the primary cause of post-mortem muscle degradation in chum salmon [14,16] and mackerel [2]. To determine the existence of proteolytic enzymes that are active under weak acidic conditions, we have measured enzyme activity at pH 6.2.…”