Proteolytic Activity of Skeletal Muscle of Normal and Dystrophic Chickens and Rabbits

1966 ◽  
Vol 6 (4) ◽  
pp. 269-278 ◽  
Author(s):  
A.A. Iodice ◽  
V. Leong ◽  
I.M. Weinstock
Keyword(s):  
Skeletal Muscle ◽  
Proteolytic Activity

Activity and expression of the 20S proteasome are increased in skeletal muscle during sepsis

1999 ◽  
Vol 277 (2) ◽  
pp. R434-R440 ◽  
Author(s):  
Scott C. Hobler ◽  
Arthur Williams ◽  
David Fischer ◽  
Jing Jing Wang ◽  
Xiaoyan Sun ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Proteolytic Activity ◽  
Blot Analysis ◽  
20S Proteasome ◽  
Catalytic Core ◽  
Proteolytic Pathway ◽  
Ubiquitin Proteasome ◽  
Dependent Protein ◽  
26S Protease

Recent studies suggest that sepsis stimulates ubiquitin-dependent protein breakdown in skeletal muscle. In this proteolytic pathway, ubiquitinated proteins are recognized, unfolded, and degraded by the multicatalytic 26S protease complex. The 20S proteasome is the catalytic core of the 26S protease complex. The role of the 20S proteasome in the regulation of sepsis-induced muscle proteolysis is not known. We tested the hypothesis that sepsis increases 20S proteasome activity and the expression of mRNA for various subunits of this complex. Proteolytic activity of isolated 20S proteasomes, assessed as activity against fluorogenic peptide substrates, was increased in extensor digitorum longus muscles from septic rats. The proteolytic activity was inhibited by specific proteasome blockers. Northern blot analysis revealed an approximately twofold increase in the relative abundance of mRNA for the 20S α-subunits RC3 and RC9 and the β-subunit RC7. However, Western blot analysis did not show any difference in RC9 protein content between sham-operated and septic rats. The increased activity and expression of the 20S proteasome in muscles from septic rats lend further support for a role of the ubiquitin-proteasome-pathway in the regulation of sepsis-induced muscle proteolysis.

scholarly journals Proteolytic Activity of Rat Skeletal Muscle

1960 ◽  
Vol 235 (3) ◽  
pp. 665-668 ◽  
Author(s):  
Thomas R. Koszalka ◽  
Leon L. Miller
Keyword(s):  
Skeletal Muscle ◽  
Proteolytic Activity ◽  
Rat Skeletal Muscle

scholarly journals Proteolytic Activity of Rat Skeletal Muscle

1960 ◽  
Vol 235 (3) ◽  
pp. 669-672
Author(s):  
Thomas R. Koszalka ◽  
Leon L. Miller
Keyword(s):  
Skeletal Muscle ◽  
Proteolytic Activity ◽  
Rat Skeletal Muscle

Proteasome proteolytic activity in skeletal muscle is increased in patients with sepsis

2007 ◽  
Vol 112 (9) ◽  
pp. 499-506 ◽  
Author(s):  
Maria Klaude ◽  
Katarina Fredriksson ◽  
Inga Tjäder ◽  
Folke Hammarqvist ◽  
Bo Ahlman ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Proteolytic Activity ◽  
Prolonged Mechanical Ventilation ◽  
Multiple Organ ◽  
Proteasome Activity ◽  
Control Group ◽  
Icu Patients ◽  
Leg Muscles ◽  
Skeletal Muscle Wasting ◽  
Leg Muscle

Patients with sepsis in the ICU (intensive care unit) are characterized by skeletal muscle wasting. This leads to muscle dysfunction that also influences the respiratory capacity, resulting in prolonged mechanical ventilation. Catabolic conditions are associated with a general activation of the ubiquitin–proteasome pathway in skeletal muscle. The aim of the present study was to measure the proteasome proteolytic activity in both respiratory and leg muscles from ICU patients with sepsis and, in addition, to assess the variation of proteasome activity between individuals and between duplicate leg muscle biopsy specimens. When compared with a control group (n=10), patients with sepsis (n=10) had a 30% (P<0.05) and 45% (P<0.05) higher proteasome activity in the respiratory and leg muscles respectively. In a second experiment, ICU patients with sepsis (n=17) had a 55% (P<0.01) higher proteasome activity in the leg muscle compared with a control group (n=10). The inter-individual scatter of proteasome activity was larger between the patients with sepsis than the controls. We also observed a substantial intra-individual difference in activity between duplicate biopsies in several of the subjects. In conclusion, the proteolytic activity of the proteasome was higher in skeletal muscle from patients with sepsis and multiple organ failure compared with healthy controls. It was shown for the first time that respiratory and leg muscles were affected similarly. Furthermore, the variation in proteasome activity between individuals was more pronounced in the ICU patients for both muscle types, whereas the intra-individual variation between biopsies was similar for ICU patients and controls.

scholarly journals Studies on proteolytic activity in commercial myoglobin preparations

1971 ◽  
Vol 125 (3) ◽  
pp. 865-868 ◽  
Author(s):  
D. F. Goldspink ◽  
D. Holmes ◽  
R. J. Pennington
Keyword(s):  
Skeletal Muscle ◽  
Proteolytic Activity ◽  
Enzyme Preparation ◽  
Soluble Fraction ◽  
Maximum Activity ◽  
Soya Bean ◽  
Exclusion Limit ◽  
Bean Trypsin Inhibitor ◽  
Myofibril Preparation ◽  
Nitrophenyl Ester

Commercial myoglobin preparations from horse skeletal muscle degraded casein. The maximum activity was at pH8–8.5. A muscle myofibril preparation was also attacked. The protease could be partly separated from the myoglobin by selective ultrafiltration through a membrane with an exclusion limit of mol.wt. 30000. A greater than 1000-fold purification of the proteolytic activity was achieved by affinity chromatography with soya-bean trypsin inhibitor bound to CM-cellulose. The enzyme preparation hydrolysed p-toluenesulphonyl-l-arginine methyl ester and N-benzyloxycarbonyl-l-tyrosine p-nitrophenyl ester. Its activity was inhibited strongly by soya-bean and ovomucoid trypsin inhibitors, serum and the soluble fraction of muscle homogenates. EDTA, p-chloromercuribenzoate and phenylmethylsulphonyl fluoride also caused some inhibition.

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