Characterization of proteolysis in muscle tissues of sea cucumber Stichopus japonicus

Abstract

The proteolysis in muscle tissues of sea cucumber (sjMTs) was characterized. The proteins from sjMTs were primarily myosin heavy chains (MHCs), paramyosin (Pm), and actin (Ac) having a molecular mass of approximately 200, 98, and 42 kDa, respectively. Based on SDS-PAGE analysis and quantification of trichloroacetic acid (TCA)-soluble peptides released, degradation of muscle proteins from sjMTs was favorable at pH 5 and 50°C. Proteolysis of MHCs was mostly inhibited by cysteine protease inhibitors, including-epoxysuccinyl-L-leucyl-amido (4-guanidino) butane (E-64) and antipain (AP). E-64 and AP completely inhibited the degradation of Pm and Ac, while iodoacetic acid showed a partially inhibitory effect. These results indicated that the proteolysis of sjMTs was mainly attributed to cysteine proteases. Avoidance of setting the tissues at 40-50°C and slightly acidic condition and inhibition of cysteine proteases are helpful for decreasing sea cucumber autolysis.

Oxidative stress involved in textural changes of sea cucumber Stichopus japonicus body wall during low-temperature treatment

“…Currently, 14 members of the caspase family have been discovered in mammalian organisms mainly involved in interacting with the upstream adaptor molecules and down-stream caspases. [8] In sea cucumber, cysteine proteases could affect the proteolysis of noncollagenous proteins [9] and muscle tissues, [10] which also suggested the cysteine proteases should be brought attention during tenderization. Mitogen-activated protein kinases (MAPK), including extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK) and p38 MAPK, are serine-threonine kinases that play important roles in a variety of cellular activities.…”

Characteristics of the Intestine Extracts and Their Effect on the Crude Collagen Fibers of the Body Wall from Sea Cucumber Apostichopus japonicus

“…An important phenomenon of sea cucumber body wall softening is protein degradation, which is primarily caused by several different endogenous enzymes, including alkaline proteinase [7], matrix metalloproteinase [12], and gelatinolytic metalloproteinase [13]. Zhao et al confirmed that the degradation of sea cucumber muscle layer proteins is related to serine proteases and cysteine proteases [14]. However, the characteristics of endogenous enzymes in the sea cucumber intestine and their effect on the property changes of collagen fibers are still unclear.…”

Investigation of structural proteins in sea cucumber (Apostichopus japonicus) body wall

“…Collagens account for about 70% of the total protein mass of the body wall and are widely considered as the most important structural proteins of sea cucumbers 13 . Besides, a few other proteins in the sea cucumber body wall have been respectively characterized, including myosin 14 , paramyosin 14 , actin 14 , fibropellin 15 , tenascin 15 , tensilin 16 , 17 , stiparin 18 , and fibrillin 19 , 20 .…”