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THE ACCESSIBILITY OF BOVINE RHODOPSIN IN PHOTORECEPTOR MEMBRANES
Bovine photoreceptor membranes have been treated with proteases to determine the accessibility of rhodopsin to these large, water soluble molecules. The polypeptides that remain associated with the membranous structure after proteolysis were detected by sodium dodecyl sulfate gel electrophoresis. Th...
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Formato: | Texto |
Lenguaje: | English |
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The Rockefeller University Press
1974
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2110932/ https://www.ncbi.nlm.nih.gov/pubmed/4417532 |
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author | Saari, John C. |
author_facet | Saari, John C. |
author_sort | Saari, John C. |
collection | PubMed |
description | Bovine photoreceptor membranes have been treated with proteases to determine the accessibility of rhodopsin to these large, water soluble molecules. The polypeptides that remain associated with the membranous structure after proteolysis were detected by sodium dodecyl sulfate gel electrophoresis. Thermolysin and chymotrypsin degraded rhodopsin (apparent mol wt 35,000–36,000) to fragments of 29,000 and 23,000 apparent mol wt, respectively, without affecting the chromophoric absorption of the molecule or removing the region of the polypeptide carrying carbohydrate. The two fragments were isolated and their amino acid compositions were determined. They do not appear to be more hydrophobic than rhodopsin. Subtilisin, at low concentration and temperature, produced a fragment with the same molecular weight as that produced by thermolysin. At higher concentrations, subtilisin yields major fragments of mol wt 23,000 and 20,000 without affecting the chromophoric absorption. Two intermediate fragments of apparent mol wt 29,000 and 26,000 were detected during the course of this degradation. Carbohydrate is retained by all but the smallest fragment. Bleaching of the photoreceptor pigment did not appreciably alter any of the fragmentation patterns. Trypsin did not alter the molecular weight of rhodopsin under the conditions of this study. Approximately 35–45% of rhodopsin appears to be accessible to the aqueous environment and can be removed without affecting the chromophoric properties of the retinaldehyde-carrying region which remains bound to the membrane. |
format | Text |
id | pubmed-2110932 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1974 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21109322008-05-01 THE ACCESSIBILITY OF BOVINE RHODOPSIN IN PHOTORECEPTOR MEMBRANES Saari, John C. J Cell Biol Article Bovine photoreceptor membranes have been treated with proteases to determine the accessibility of rhodopsin to these large, water soluble molecules. The polypeptides that remain associated with the membranous structure after proteolysis were detected by sodium dodecyl sulfate gel electrophoresis. Thermolysin and chymotrypsin degraded rhodopsin (apparent mol wt 35,000–36,000) to fragments of 29,000 and 23,000 apparent mol wt, respectively, without affecting the chromophoric absorption of the molecule or removing the region of the polypeptide carrying carbohydrate. The two fragments were isolated and their amino acid compositions were determined. They do not appear to be more hydrophobic than rhodopsin. Subtilisin, at low concentration and temperature, produced a fragment with the same molecular weight as that produced by thermolysin. At higher concentrations, subtilisin yields major fragments of mol wt 23,000 and 20,000 without affecting the chromophoric absorption. Two intermediate fragments of apparent mol wt 29,000 and 26,000 were detected during the course of this degradation. Carbohydrate is retained by all but the smallest fragment. Bleaching of the photoreceptor pigment did not appreciably alter any of the fragmentation patterns. Trypsin did not alter the molecular weight of rhodopsin under the conditions of this study. Approximately 35–45% of rhodopsin appears to be accessible to the aqueous environment and can be removed without affecting the chromophoric properties of the retinaldehyde-carrying region which remains bound to the membrane. The Rockefeller University Press 1974-11-01 /pmc/articles/PMC2110932/ /pubmed/4417532 Text en Copyright © 1974 by The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/). |
spellingShingle | Article Saari, John C. THE ACCESSIBILITY OF BOVINE RHODOPSIN IN PHOTORECEPTOR MEMBRANES |
title | THE ACCESSIBILITY OF BOVINE RHODOPSIN IN PHOTORECEPTOR MEMBRANES |
title_full | THE ACCESSIBILITY OF BOVINE RHODOPSIN IN PHOTORECEPTOR MEMBRANES |
title_fullStr | THE ACCESSIBILITY OF BOVINE RHODOPSIN IN PHOTORECEPTOR MEMBRANES |
title_full_unstemmed | THE ACCESSIBILITY OF BOVINE RHODOPSIN IN PHOTORECEPTOR MEMBRANES |
title_short | THE ACCESSIBILITY OF BOVINE RHODOPSIN IN PHOTORECEPTOR MEMBRANES |
title_sort | accessibility of bovine rhodopsin in photoreceptor membranes |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2110932/ https://www.ncbi.nlm.nih.gov/pubmed/4417532 |
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