title: Effect of gamma radiation on the structural and biological properties of angiotensin II.
abstract: OBJECTIVE
  The vasoactive octapeptide hormone angiotensin II (DRVYIHPF, AngII) was selected as the target of this2investigation, which was aimed at determining the effect of gamma radiation on peptide structure and biological activity.
  
  
  METHODS
  Radiation doses ranging from 1-15 kGy were applied to samples of purified AngII.
  
  
  RESULTS
  The measured amount of remaining native hormone decreased non-linearly as the gamma radiation dose increases. Amino acid analysis of these irradiated peptide solutions demonstrated similar, simultaneous modifications of Phe8 and His6 residues along with the increase in the radiation dose. This structural variation of the vasoactive peptide closely resembled the decreasing process of the biological potencies of irradiated peptide solutions in rat uterus and guinea pig ileum muscle preparations.
  
  
  CONCLUSIONS
  These findings suggest that investigating the effect of gamma radiation on small model molecules such as peptides could be of value for further extending this type of study to other physiologically relevant macromolecules such as proteins. Of note, this unique approach could also be useful in generating different types of peptide analogs (after purification) for application in future classical structure-function studies.
authors.affiliation: Department of Biophysics-Federal University of São Paulo (UNIFESP), São Paulo, Brazil.
authors.forename: Daniela T
authors.initials: DT
authors.lastname: Nardi
authors.forename: Murilo S
authors.initials: MS
authors.lastname: Casare
authors.forename: Luis G D
authors.initials: LG
authors.lastname: Teixeira
authors.forename: Nanci
authors.initials: N
authors.lastname: Nascimento
authors.forename: Clovis R
authors.initials: CR
authors.lastname: Nakaie
mesh_terms: D000804:Angiotensin II / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005720:Gamma Rays; D006168:Guinea Pigs; D007082:Ileum / Q000378:metabolism / Q000528:radiation effects; D051381:Rats; D014599:Uterus / Q000378:metabolism / Q000528:radiation effects
chemical_list: D000804:Angiotensin II