Degradation of myofibrillar proteins by trypsin-like serine proteinases.

Abstract

The effects of the Ca2+-activated cysteine proteinase, the rat trypsin-like serine proteinase and bovine trypsin on myofibrillar proteins from rabbit skeletal muscle are compared. 2. Myofibrils that had been treated at neutral pH with the Ca2+-dependent proteinase and with the rat enzyme were (a) analyzed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and (b) examined in the electron microscope. Treatment with each proteinase resulted in the loss of the Z-discs, but the rat enzyme caused much more extensive disruption of the ultrastructure and degraded more of the myofibrillar proteins. 3. Purified F-actin was almost totally resistant to the proteinases, whereas G-actin was degraded by the rat trypsin-like proteinase at a rate approx. 15 times faster than was obtained with bovine trypsin. 4. Similar results were obtained with alpha-actinin, whereas tropomyosin was degraded more readily by bovine trypsin than by the rat trypsin-like proteinase. 5. The implications of these findings for the non-lysosomal breakdown of myofibrillar proteins in vivo are considered.

Purification and characterization of myofibril-bound serine protease from crucian carp Carassius giberio langsdorfi muscle

“…Although, according to the reports of Kay et al. a certain intracellular serine protease mainly participates in initial degradation of myofibrillar proteins in mouse muscle, 1,2 only a few studies have been reported on intracellular serine protease in fish muscle. According to the previous studies, fish muscle serine proteases are roughly divided into two groups on the basis of the behavior of solubility in muscle homogenate.…”

“…These results revealed that crucian carp MBSP possesses enzyme activity in vivo . Kay et al 1,2 . suggested that endogenous serine protease mainly participates in initial degradation process of myofibrillar proteins.…”

“…These results revealed that crucian carp MBSP possesses enzyme activity in vivo. Kay et al 1,2 suggested that endogenous serine protease mainly participates in initial degradation process of myofibrillar proteins. In light of the previous discussion, it is suggested that MBSP plays a vital role in the muscle protein metabolism and, therefore, future study is necessary to clarify its physiological function.…”

Purification and Characterization of a Myofibril-Bound Serine Proteinase From the Skeletal Muscle of Silver Carp

“…2000). Except calpains (Mykles and Skinner 1983), proteinases involved in the nonlysosomal pathway have been characterized as serine proteinases (Kay et al. 1982a,b).…”

Ultrastructural stereological analysis of absolute parameters of cardiomyocytes exposed to contrasting temperature effects

“…The destruction of myofibrils and mitochondria as well as other sarcoplasmic organelles reportedly occurs in different ways [9]. Degradation of myofibrilar structures is probably a two-step process: first they are destroyed by neutral and basic proteases [11,12] and then their residues are utilized by lysosomal enzymes [10]. Lysosomes alone accomplish the destruction of mitochondria [14].…”