ISSN:
0275-3723
Keywords:
epidermal growth factor
;
epidermal growth factor receptor
;
integral membrane proteins
;
hormone receptor
;
limited proteolysis
;
Chemistry
;
Molecular Cell Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Microsomal membranes from human placenta, which bind 5-20 pmol of 125I-epidermal growth factor (EGF) per mg protein, have been affinity-labeled with 125I-EGF either spontaneously or with dimethylsuberimidate. Coomassie blue staining patterns on SDS polyacrylamide gels are minimally altered, and the EGF-receptor complex appears as a specifically labeled band of 180,000 daltons which is not removed by urea, neutral buffers, or chaotropic salts but is partially extracted by mild detergents. Limited proteolysis by alpha chymotrypsin and several other serine proteases yields labeled fragments of 170,000, 130,000, 85,000, and 48,000 daltons. More facile cleavage by papain or bromelain rapidly degrades the hormone-receptor complex to smaller labeled fragments of about 35,000 and 25,000 daltons. These fragments retain the binding site for EGF, are capable of binding EGF, and remain associated with the membrane. Alpha chymotryptic digestion of receptor solubilized by detergents yields the same fragments obtained with intact vesicles, suggesting that the fragments may represent intrinsic proteolytic domains of the receptor.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jsscb.1981.380150103
Permalink
