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RISS 인기검색어
- 검색키워드
- 저자 : Smeby, (검색결과 2 건)
- 무료
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Synthesis of Isoleucyl^5-Alanyl^7-Angiotensin Ⅱ
Seu, Jung-Hwn,Smeby, Rbert R.,Bumpus, F. Merlin 慶北大學校 1962 論文集 Vol.6 No.-
The octapeptide isoleucyl -alanyl -angiotensin Ⅱ has been synthesized in order to study further the significance of structure at the C-terminal end of angiotesin Ⅱ for biological activity. This replacement of proline, in position 7 of angiotensin Ⅱ, by alanine, greatly reduced the pressor and oxytocic activites of the peptide. This marked loss of activity, by merely removing two methylene groups of the proline ring, may be caused by a changing of the confermation at the C-terminus of the peptide. Addition of urea to an aqueous solution of angiotensin Ⅱ greatly reduces its myotrpohic action and also causes a marked reduction in degree of order showing bythe peptide as studied, by optical rotatory dispersion. From this it follows that the conformation of the peptide is an important factor for the myotrophic activity. Isoleucyl -angiotensin Ⅱ, the octapeptide L-aspartyl-L-arginyl-L-valyl-L_tyrosyl-L-isoleucyl-L-histidyl-L-prolyl-L-phenylalanine, exhibits marked specificty of structure at the C-terminus for pressor and myotrophic activities. Removal of L-phenylalanine or only the aromatic ring of this amino acid destroys the biological activities of the peptide. Conversion of the C-terminal carboxyl group to an amide group causes some reduction in biological activities. The phenolic ring of tyrosine and the imidazole ring of histidine have also been reported to be essential for the biological activities of the peptide. A conformation recently suggested for angiotensin Ⅱ , based on the assumption it will form anα-helix to the greatest extent possible, will explain all physical and biological data presently known for this peptide. In this conformation the groups essential for biological activity are all arranged in close proximity and on the same side of the molecule. Since rupture of the aliphatic ring of proline would change the stucture at the C-terminus of the peptide and would alter the relative position of these essential groups, we have replaced proline in angiotensin Ⅱ with alanine by the preparation of isoleucyl -ananyl angiotensin Ⅱ.
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SYNTHESIS OF ALANYL^4-ISOLEUCYL^5-ANGIOTENSIN Ⅱ
Seu, Jung-Hwn,Robert R. Smeby,F. M. Bumpus 慶北大學校 1962 論文集 Vol.6 No.-
Resent studies on analogues and homologues of angiotensin I, the pressor octapeptide L-aspart1-L-arginyl-L-valyl-L-tyrosyl-L-histidyl-L-prolyl-L-phenylalanine, have shown the two amino acids with aomatic rings are important to biological activity. Removal of the aromatic ring of phenylalanine greatly reduced pressor activity. The peptide without the phenolic hydroxy group of tyrosine, phenylalanine angiotensin, has only 2 to 10% of the activity of the parent octapeptide. The two aromatic side gropes are positioned, very close to each other in a conformation recently suggested for angiotensin I.
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