Specific binding sites for prohormone atrial natriuretic peptides 1-30, 31-67 and 99-126.
Two peptides with vasodilatory properties consisting of amino acids 1-30 and 31-67 of the 98 a.a. N-terminal end of the prohormone of atrial natriuretic factor (proANF) which circulates in man were investigated to determine if they have specific binding sites on membranes isolated from DDT1 MF-2 smooth muscle cells. Smooth muscle is a known biologic target of these peptides. Competitive binding experiments revealed that proANFs (1-30), (31-67), and (99-126) (i.e., C-terminus; ANF) each had specific and separate binding sites. The dissociation constants for proANFs (1-30), (31-67), and (99-126) binding were 0.11 nM, 4 nM, and 7.3 nM, respectively. The binding site concentrations for proANFs (1-30), (31-67), and ANF were 2.57, 59.91 and 40 fmols/10(6) cells, respectively. The number of binding sites per cell were 1548, 36,087, and 24,090, respectively, for proANFs (1-30), (31-67), and (99-126) (ANF). Each peptide bound to DDT1 MF-2 membranes between 10(-8) to 10(-11) M but could only bind to the other peptides' receptors at concentrations of 10(-6) and 10(-7)M. These results suggest that proANF(1-30) and proANF(31-67) do not work through the ANF receptor but rather have their own separate and distinct receptors that mediate their biologic effects.
Vesely
D L
DL
Department of Medicine, University of Arkansas for Medical Sciences, Little Rock.
Cornett
L E
LE
MacLeod
S L
SL
Nash
A A
AA
Norris
J S
JS
D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D001667:Binding, Competitive; D002462:Cell Membrane / Q000032:analysis / Q000378:metabolism; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D009130:Muscle, Smooth / Q000032:analysis* / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism*; D017461:Receptors, Atrial Natriuretic Factor; D011956:Receptors, Cell Surface / Q000032:analysis* / Q000378:metabolism
D010446:Peptide Fragments; D011498:Protein Precursors; D011956:Receptors, Cell Surface; C054547:atrial natriuretic factor prohormone (1-30), human; C054548:atrial natriuretic factor prohormone (31-67); D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor