A structural comparison of guinea pig thyroid and fat TSH receptors by photoaffinity labelling

PR Buckland, BR Smith - FEBS letters, 1984 - Elsevier
PR Buckland, BR Smith
FEBS letters, 1984Elsevier
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 …
Abstract
TSH receptors from guinea pig thyroid and epididymal fat have been covalently crosslinked to 125I-labelled TSH conjugated to N-hydroxysuccinimidyl-4-azidobenzoate. Analysis by SDS—PAGE and autoradiography showed bands corresponding to TSH subunits (Mr 14 000) and intact TSH (Mr 28 000; subunits crosslinked) and two at higher Mr separated by 14 000. The latter bands represented one or two subunits of TSH crosslinked to a subunit of the TSH receptor with Mr 57 000 (fat) or 60 000 (thyroid). These Mr 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 Mr 30 000.
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