ATRIAL NATRIURETIC PEPTIDE BINDING SITES ON HOG CILIARY BODIES AND CHOROID

抄録

Binding studies revealed the presence of two classes of binding sites for atrial natriuretic peptide (ANP) on hog ciliary bodies and choroid membranes. The curvilinear Scatchard plots were evaluated by nonlinear regression analysis using a twosite model which identified a high affinity site K_d1=73±12 pM and B_max1=77±7 fmol/mg protein, and a low affinity site K_d2=0.748±0.199 nM and B_max2= 44±11 fmol/mg protein in ciliary bodies, and a high affinity site K_d1=45±3 pM and B_max1= 44±2 fmol/mg protein, and a low affinity site K_d2=1.181±0.356 nM and B_max2=158±44 fmol/mg protein in choroid. Affinity labeling with disuccinimidyl suberate followed by electrophoresis under nonreducing condition and autoradiography show that the peptide binds predominantly to 66,000 dalton species on membrane of ciliary bodies. However, on membrane of choroid, the high molecular size protein (130,000 dalton species) is intensely labeled. The results suggest that a polypeptide of 66,000 dalton represents a component of the high affinity ANP receptor.