title: Rat atrial natriuretic factor: isolation, structure and biological activities of four major peptides.
abstract: Four peptides possessing both natriuretic activity and smooth muscle relaxant activity were isolated from rat atrium and their amino acid sequences determined. The four peptides designated ANF-I, ANF-II, ANF-III and ANF-IV containing 35, 31, 30 and 25 amino acid residues, respectively, were obtained in a molar ratio of 4:60:20:16. The predominant species ANF-II, which may represent the native form of ANF, has the following sequence: (H2N)-G-P-R-S-L-R-R-S-S-C-F-G-G-R-I-D-R-I-G-A-Q-S-G-L-G-C-N-S-F-R-Y-(COO H) in which Cys-10 and Cys-26 are disulfide linked. Cleavage of the aspartyl linkage at position 16 by staphylococcal protease caused complete inactivation, indicating that the ring conformation is essential. The dose-response relationships determined for the four peptides in relaxing norepinephrine-induced contraction of rabbit thoracic aorta showed half-maximum relaxation at concentrations ranging from 1.5 X 10(-9) to 2.5 X 10(-9) M. Comparable dose-response relationships were observed in relaxation of carbacol-induced contraction of chick rectum strips as tested with ANF-II and ANF-IV.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D009320:Atrial Natriuretic Factor; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D006325:Heart Atria / Q000032:analysis; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009206:Myocardium / Q000032:analysis*; D045283:Natriuretic Agents; D010446:Peptide Fragments / Q000032:analysis; D011506:Proteins / Q000302:isolation & purification* / Q000494:pharmacology; D051381:Rats; D014357:Trypsin / Q000378:metabolism
chemical_list: D045283:Natriuretic Agents; D010446:Peptide Fragments; D011506:Proteins; C472610:atrial natriuretic peptide, rat; D009320:Atrial Natriuretic Factor; D014357:Trypsin