In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 69, No. 5 ( 1972-05), p. 1168-1172
Abstract:
Electroplax, single cells dissected from electric tissue of Electrophorus , are labeled in a two-step procedure: reduction by dithiothreitol followed by alkylation by the affinity label 4-( N -maleimido)-α-benzyltri-[methyl- 3 H]methylammonium iodide, either alone or in combination with [2,3- 14 C] N -ethylmaleimide. Electrophoresis in sodium dodecyl sulfate on polyacrylamide gel of an extract, prepared with this detergent, of single-labeled or of double-labeled cells results in a major peak of 3 H activity, with a mobility corresponding to a polypeptide of molecular weight 42,000. In addition, in the double-labeled samples, there is a unique peak in the ratio of 3 H to 14 C that is coincident with the 3 H peak. The electrophoretic patterns of extracts of cells in which affinity alkylation of the reduced receptor has been suppressed by dithiobischoline, an affinity oxidizing agent, by cobratoxin, an irreversible ligand, or by hexamethonium, a reversible ligand, show a considerably diminished peak of 3 H activity in the region of molecular weight 42,000. This is the predominant difference between the electrophoretic patterns of extracts of unprotected and of protected cells. Furthermore, extracts of cells protected with dithiobischoline before labeling with both tritiated affinity label and [ 14 C] N -ethylmaleimide do not show the peak in the 3 H to 14 C ratio seen in the absence of protection. Thus, by several diverse criteria, the peak of 3 H activity corresponding to a molecular weight of 42,000 contains affinity-labeled acetylcholine receptor or receptor subunit.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.69.5.1168
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
1972
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
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