Atrial natriuretic peptide binds to ANP-R1 receptors in neuroblastoma cells or is degraded extracellularly at the Ser-Phe bond.
ANP-R1 receptors for atrial natriuretic peptide (ANP) showed the following rank order of affinity in intact human neuroblastoma cells NB-OK-1: human ANP-(99-126) approximately human ANP-(102-126) approximately rat ANP-(99-126) (K1 17-32 pM) > human ANP-(103-126) > porcine brain natriuretic peptide (BNP). Analogues truncated at the C-terminal extremity or devoid of a disulphide bridge, such as rat ANP-(103-123), rat C-ANP-(102-121), rat ANP-(111-126), rat ANP-(99-109) and rat [desCys105,Cys121]ANP-(104-126) and chicken C-type natriuretic peptide, were not recognized. The occupancy of these high affinity ANP-R1 receptors led to marked cyclic GMP accumulation in the presence of 3-isobutyl 1-methylxanthine. An ectoenzymic activity, partly shed in the incubation medium, provoked the stepwise release of Phe-Arg-[125I]Tyr, Arg-[125I]Tyr and [125I]Tyr from rat [125I]ANP-(99-126), at an optimal pH of 7.0. Its inhibition by 1,10-phenanthroline, EDTA and bacitracin but not by thiorphan suggests the contribution of at least one neutral metalloendopeptidase, distinct from EC 3.4.24.11, for which ANP showed high affinity.
Delporte
C
C
Department of Biochemistry and Nutrition, Medical School, Université Libre de Bruxelles, Belgium.
Poloczek
P
P
Tastenoy
M
M
Winand
J
J
Christophe
J
J
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism* / Q000494:pharmacology; D002470:Cell Survival; D002645:Chickens; D002851:Chromatography, High Pressure Liquid; D006152:Cyclic GMP / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007457:Iodine Radioisotopes; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D008666:Metalloendopeptidases / Q000378:metabolism; D009447:Neuroblastoma / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism; D051381:Rats; D017461:Receptors, Atrial Natriuretic Factor / Q000378:metabolism*; D013552:Swine; D014407:Tumor Cells, Cultured
D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D009320:Atrial Natriuretic Factor; D007770:L-Lactate Dehydrogenase; D008666:Metalloendopeptidases; D017461:Receptors, Atrial Natriuretic Factor; D006152:Cyclic GMP