title: Effect of proteolysis on the electron spin resonance spectra of maleimide spin labeled erythrocyte membrane.
abstract: The ratio of low-field amplitudes of weakly and strongly immobilized signals of ESR spectra of a maleimide spin label bound to erythrocyte membranes (hw/hs) increases progressively during incubation at 37 degrees C. This increase is due to the 'self-digestion' of membrane proteins by endogenous proteinases and is attenuated by proteinase inhibitors. Digestion of membranes with chymotrypsin also increases the hw/hs ratio. These results suggest a need for a careful interpretation of data from spin-labeled membrane proteins, especially in experiments involving prolonged incubations of membrane preparations when the proteolytic effects may be significant.
mesh_terms: D000818:Animals; D002417:Cattle; D002918:Chymotrypsin / Q000378:metabolism; D003497:Cyclic N-Oxides / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D004910:Erythrocyte Membrane; D006868:Hydrolysis; D008565:Membrane Proteins / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D013113:Spin Labels / Q000378:metabolism; D013696:Temperature; D013997:Time Factors
chemical_list: D003497:Cyclic N-Oxides; D008565:Membrane Proteins; D011480:Protease Inhibitors; D013113:Spin Labels; C017480:4-maleimido-2,2,6,6-tetramethylpiperidinooxyl; D002918:Chymotrypsin