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A structural comparison of guinea pig thyroid and fat TSH receptors by photoaffinity labelling
Author(s) -
Buckland Paul R.,
Rees Smith Bernard
Publication year - 1984
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(84)80054-x
Subject(s) - labelling , guinea pig , photoaffinity labeling , receptor , thyroid , chemistry , endocrinology , affinity label , medicine , biochemistry
TSH receptors from guinea pig thyroid and epididymal fat have been covalently crosslinked to 125 I‐labelled TSH conjugated to N ‐hydroxysuccinimidyl‐4‐azidobenzoate. Analysis by SDS—PAGE and autoradiography showed bands corresponding to TSH subunits ( M r 14 000) and intact TSH ( M r 28 000; subunits crosslinked) and two at higher M r separated by 14 000. The latter bands represented one or two subunits of TSH crosslinked to a subunit of the TSH receptor with M r 57 000 (fat) or 60 000 (thyroid). These M r values were reduced by trypsin treatment to 43 000 and 50 000, respectively. Analysis under non‐reducing conditions showed that both fat and thyroid receptors have a second disulphide linked subunit of M r 30 000.