title: Tryptophan exposure in various conformational isomers of bovine prothrombin fragment 1. An acrylamide quenching study.
abstract: In order to assess the importance of a variety of environmental factors on the structure of bovine prothrombin fragment 1, we have examined acrylamide quenching of fragment 1 intrinsic fluorescence. Tryptophan exposure, determined from Stern-Volmer plots, is heterogeneous with one or more of the three fragment 1 tryptophans being exposed to solvent. In the presence of Ca2+ or Mg2+ even the most accessible tryptophan(s) are relatively buried. Only small differences in tryptophan exposure may exist between fragment 1-Ca2+ and fragment 1-Mg2+ complexes. Lowering pH, on the other hand, results in increased tryptophan exposure. Finally, structural isomers of fragment 1 which exist in the absence of metal ions have identical tryptophan exposure as determined by acrylamide quenching and fluorescence intensity.
mesh_terms: D000178:Acrylamides; D000818:Animals; D002118:Calcium; D002417:Cattle; D006863:Hydrogen-Ion Concentration; D007536:Isomerism; D007700:Kinetics; D008274:Magnesium; D010446:Peptide Fragments; D011487:Protein Conformation; D011498:Protein Precursors; D011516:Prothrombin; D013050:Spectrometry, Fluorescence; D014364:Tryptophan
chemical_list: D000178:Acrylamides; D010446:Peptide Fragments; D011498:Protein Precursors; C029733:prothrombin fragment 1; D014364:Tryptophan; D011516:Prothrombin; D008274:Magnesium; D002118:Calcium