[Spectroscopic study of the structural changes of scorpion hemocyanin, induced by pH variations and addition of various salts].
Structural modifications of the scorpion haemocyanin induced by pH variations and salt addition are studied by U.V. absorption, fluorescence, circular dichroism and light scattering. Haemocyanin fluorescence is due to both aromatic amino-acids tyrosine and tryptophan. Deoxygenation or denaturation lead to a fourfold enhancement of its intensity. At acidic pH the active site is modified and the protein is dissociated, but at alkaline pH the haemocyanin aggregates. The addition of different salts (sodium citrate, potassium bromide and iodide...) involves protein dissociation, the amplitude of which depends on the anion. But pH variations and salt addition don't change the haemocyanin secondary structure as shown by circular dichroism. The C.D. spectrum of scorpion haemocyanin exhibits the characteristic bands of Arthropod haemocyanine.
D000818:Animals; D000838:Anions; D002942:Circular Dichroism; D006433:Hemocyanins; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances; D010100:Oxygen; D011487:Protein Conformation / Q000187:drug effects; D012605:Scorpions; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014364:Tryptophan; D014443:Tyrosine; D014508:Urea / Q000494:pharmacology
D000838:Anions; D046911:Macromolecular Substances; D014443:Tyrosine; D014364:Tryptophan; D014508:Urea; D006433:Hemocyanins; D010100:Oxygen
Etude spectroscopique des modifications structurales de l'hémocyanine de scorpion induites par les variations de pH et l'addition de différents sels