Calpain activity in a subcellular fraction enriched in partially degraded CNS myelin fragments compared with myelin.
Marchi-positive bodies are structures present paranodally in large myelinated nerve fibers. They have morphological and biochemical characteristics closely resembling the partially degraded myelin fragments formed during the early phases of Wallerian degeneration. Levels of calcium-activated neutral proteases (calpains) and their endogenous specific inhibitor calpastatin were measured in highly purified rabbit myelin and a spinal cord subcellular light ('floating') fraction heavily enriched in Marchi-positive bodies. Calpain levels were found to be significantly higher in the floating fraction as compared to myelin. No calpastatin was detectable in either fraction.
Persson
H
H
University of Gothenburg, Department of Anatomy, Sweden.
Karlsson
J O
JO
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002154:Calpain / Q000378:metabolism*; D002490:Central Nervous System / Q000201:enzymology*; D004676:Myelin Basic Protein / Q000378:metabolism; D009186:Myelin Sheath / Q000378:metabolism*; D011510:Proteolipids / Q000378:metabolism; D011817:Rabbits; D013347:Subcellular Fractions / Q000201:enzymology*
D002135:Calcium-Binding Proteins; D004676:Myelin Basic Protein; D011510:Proteolipids; C033668:calpastatin; D002154:Calpain; D002118:Calcium