Difference in molecular size of receptors for alpha-rat atrial natriuretic polypeptide among the kidney, aorta, and adrenal gland as identified by direct UV-photoaffinity labeling.
In order to identify the molecular size of receptors for alpha-rat atrial natriuretic polypeptide (alpha-rANP), we utilized the direct UV irradiation method for photoaffinity labeling with the biologically active [125I] alpha-rANP. In the preparation of isolated glomerulus and the inner medullary collecting duct (IMCT)-rich fraction, the autoradiograms of the electrophoresed sodium dodecyl sulfate (SDS)-polyacrylamide gels showed a single radioactive band which is displaceable with unlabeled alpha-rANP. The dose-dependent displacement fit very well with a binding-inhibition curve representing the binding affinity of 6.5 X 10(-10) M. The molecular size of the ligand-receptor complex was about 65,000 daltons for both glomerulus and IMCT-rich fraction. In contrast, in homogenate of the aorta and adrenal gland, the ligand-receptor complex was 140,000 daltons.
D000311:Adrenal Glands / Q000032:analysis*; D000345:Affinity Labels / Q000378:metabolism; D000818:Animals; D001011:Aorta / Q000032:analysis*; D001345:Autoradiography; D004591:Electrophoresis, Polyacrylamide Gel; D007668:Kidney / Q000032:analysis*; D008297:Male; D008970:Molecular Weight; D010777:Photochemistry; D051381:Rats; D011919:Rats, Inbred Strains; D017461:Receptors, Atrial Natriuretic Factor; D011956:Receptors, Cell Surface / Q000032:analysis*; D014466:Ultraviolet Rays
D000345:Affinity Labels; D011956:Receptors, Cell Surface; D017461:Receptors, Atrial Natriuretic Factor