Overall proteolysis and the activity of skeletal muscle proteolytic systems were investigated in rats submitted to guanethidine-induced adrenergic blockade for 4 days. In soleus, overall proteolysis increased by 15-20% during the first 2 days of guanethidine treatment but decreased to levels below control values after 4 days. Extensor digitorum longus (EDL) did not show the initial increase in ...

Proteases having a neutral pH optimum and an absolute requirement for calcium ion are found in virtually all mammalian cells. Association of calcium-dependent proteases and a specific inhibitor protein with biological membranes seems to be an important regulatory feature of this proteolytic system, and it is likely that membranes are preferred sites for calcium-dependent protease action. Severa...

The objective of the research was to study signs oxidative stress, state proteolysis, and proteinase-inhibiting system blood plasma in rats with streptozotocin-induced diabetes mellitus (60 mg/kg intra-abdominally), complicated by cerebral ischemia-reperfusion. Levels products lipid peroxide oxidation, protein modification, nitrogen oxide metabolites, activity antioxidant protection enzymes wer...

The size of von Willebrand factor (VWF) is a major determinant of its biologic activity, the largest multimers being the most efficacious in supporting platelet adhesion and aggregation during primary hemostasis.1 In the dynamic situation at the time of hemostatic challenge, if VWF possesses a normal size distribution but is more fragile through increased susceptibility to proteolysis, the effi...

Proteases can complicate the characterization of proteins from cells, especially human polymorphonuclear leukocytes (PMN), which contain abundant neutral proteases. We tested the ability of agents to inhibit proteolysis, with special reference to the subunit polypeptides of the contractile proteins actin, myosin, and actin-binding protein (ABP). Phenylmethylsulfonyl fluoride (PMSF), O-phenanthr...

Chronic acidosis is a stimulus for proteolysis in muscle in vivo, but the mechanism of this response is unknown. We tested the hypothesis that acidosis or TNF-alpha, a cytokine whose production increases in acidosis, regulates proteolysis by inhibiting insulin signaling through phosphoinositide 3-kinase (PI3K). In cultured L6 myotubes, acidified (pH 7.1) media did not accelerate the basal prote...

BACKGROUND Proteolysis, involved in many processes in living organisms, is tightly regulated in space and time under physiological conditions. However deregulation can occur with local persistent proteolytic activities, e.g. in inflammation, cystic fibrosis, tumors, or pancreatitis. Furthermore, little is known about the role of many proteases, hence there is a need of new imaging methods to vi...

The role of adrenoceptor subtypes and of cAMP on rat skeletal muscle proteolysis was investigated using a preparation that maintains tissue glycogen stores and metabolic activity for several hours. In both soleus and extensor digitorum longus (EDL) muscles, proteolysis decreased by 15-20% in the presence of equimolar concentrations of epinephrine, isoproterenol, a nonselective beta-agonist, or ...