Effect of clenbuterol on the activity of proteolytic enzymes partially purified from rat skeletal muscle

1991 ◽  
Vol 19 (2) ◽  
pp. 214S-214S ◽  
Author(s):  
TIMOTHY LEES ◽  
CHARLOTTE A. MALTIN ◽  
DAVID MANTLE
Keyword(s):  
Skeletal Muscle ◽  
Proteolytic Enzymes ◽  
Rat Skeletal Muscle

scholarly journals Skeletal muscle mitochondrial β-oxidation. A study of the products of oxidation of [U-14C]hexadecanoate by h.p.l.c. using continuous on-line radiochemical detection

1988 ◽  
Vol 253 (2) ◽  
pp. 541-547 ◽  
Author(s):  
N J Watmough ◽  
A K Bhuiyan ◽  
K Bartlett ◽  
H S Sherratt ◽  
D M Turnbull
Keyword(s):  
Skeletal Muscle ◽  
Proteolytic Enzymes ◽  
Rat Skeletal Muscle ◽  
Beta Oxidation ◽  
Citrate Cycle ◽  
Mitochondrial Fractions ◽  
On Line ◽  
14Co2 Release

Well-coupled mitochondrial fractions were prepared from rat skeletal muscle without the use of proteolytic enzymes. The products of [U-14C]hexadecanoate oxidation by rat skeletal muscle mitochondrial fractions were analysed by h.p.l.c. with on-line radiochemical detection. In the presence of 1 mM-carnitine, 70% of the products is acetylcarnitine. In agreement with Veerkamp et al. [Veerkamp, van Moerkerk, Glatz, Zuurveld, Jacobs & Wagenmakers (1986) Biochem. Med. Metab. Biol. 35, 248-259] 14CO2 release is shown to be an unreliable estimate of flux through beta-oxidation in skeletal muscle mitochondrial fractions. The flux through beta-oxidation is recorded unambiguously polarographically in the presence of 1 mM-carnitine and the absence of citrate cycle intermediates.

The ubiquitin–proteasome system and skeletal muscle wasting

2005 ◽  
Vol 41 ◽  
pp. 173-186 ◽  
Author(s):  
Didier Attaix ◽  
Sophie Ventadour ◽  
Audrey Codran ◽  
Daniel Béchet ◽  
Daniel Taillandier ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Wasting ◽  
Proteolytic Enzymes ◽  
Cathepsin L ◽  
Ubiquitin Proteasome System ◽  
Complete Breakdown ◽  
Skeletal Muscle Proteins ◽  
Ubiquitin Proteasome ◽  
Tripeptidyl Peptidase Ii ◽  
F Box Protein

The ubiquitin–proteasome system (UPS) is believed to degrade the major contractile skeletal muscle proteins and plays a major role in muscle wasting. Different and multiple events in the ubiquitination, deubiquitination and proteolytic machineries are responsible for the activation of the system and subsequent muscle wasting. However, other proteolytic enzymes act upstream (possibly m-calpain, cathepsin L, and/or caspase 3) and downstream (tripeptidyl-peptidase II and aminopeptidases) of the UPS, for the complete breakdown of the myofibrillar proteins into free amino acids. Recent studies have identified a few critical proteins that seem necessary for muscle wasting {i.e. the MAFbx (muscle atrophy F-box protein, also called atrogin-1) and MuRF-1 [muscle-specific RING (really interesting new gene) finger 1] ubiquitin–protein ligases}. The characterization of their signalling pathways is leading to new pharmacological approaches that can be useful to block or partially prevent muscle wasting in human patients.

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