Biochemical aspects of the visual process. XXIX. Effect of pronase on rod outer segment membranes and rhodopsin
| Autor: | P.J.G.M. Van Breugel, Frans J.M. Daemen, S.L. Bonting |
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| Rok vydání: | 1975 |
| Předmět: |
Rhodopsin
Proteases Cell Membrane Permeability Light genetic structures Detergents Pronase Cellular and Molecular Neuroscience Papain medicine Animals Chymotrypsin Photoreceptor Cells Trypsin Subtilisins Gel electrophoresis Binding Sites biology Chemistry Subtilisin Proteolytic enzymes Darkness Sensory Systems Alcohol Oxidoreductases Ophthalmology Membrane Biochemistry Phospholipases biology.protein Cattle Electrophoresis Polyacrylamide Gel sense organs Retinal Pigments medicine.drug |
| Zdroj: | Experimental Eye Research. 21:315-324 |
| ISSN: | 0014-4835 |
| DOI: | 10.1016/0014-4835(75)90042-1 |
| Popis: | Treatment of aqueous suspensions of bovine rod outer segment membranes with proteases (pronase, subtilisin, α-chymotrypsin, papain, trypsin) leaves rhodopsin spectrally intact and its recombination capacity is retained. Other proteins, including retinol dehydrogenase, in these membranes are rapidly attacked by all five proteases. The amount of protein solubilized during pronase treatment indicates that digestion is limited to 24–31% of total membrane protein, including a fragment of each rhodopsin molecule. Analysis of the treated membrane material by dodecyl sulfate gel electrophoresis shows that after treatment with pronase, subtilisin and α-chymotrypsin the band of native rhodopsin (36 500 Dalton) has disappeared, while distinct bands of 28 500 and 21 500 Dalton have appeared. The last two bands still contain the oligosaccharide residue present in native rhodopsin. With papain only the band of 28 500 Dalton appears, while trypsin does not affect rhodopsin at all. Prior treatment of the membranes by detergents or phospholipase C action preceding proteolytic digestion renders rhodopsin susceptible to more complete proteolytic degradation, involving loss of 500 nm absorbance. These findings suggest that a major part of the rhodopsin molecule is buried in the hydrophobic core of the membrane and therefore resists proteolytic attack, while a minor part of the native protein is exposed to the aqueous phase and may be digested by proteases. Removal of the latter fragment doses not affect the spectral properties and recombination capacity of rhodopsin, indicating that this part of the molecule has no function in maintaining these parameters. |
| Databáze: | OpenAIRE |
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