Isolation and characterization of an olfactory receptor protein for odorant pyrazines

Proc Natl Acad Sci U S A. 1985 May;82(9):3050-4. doi: 10.1073/pnas.82.9.3050.

Abstract

The highly potent bell pepper odorant 2-isobutyl-3-[3H]methoxypyrazine [( 3H]IBMP) binds specifically and saturably to bovine and rat nasal epithelium. Specific binding is not detected in 11 other tissues assayed, and in the rat binding is 9 times higher in olfactory than in respiratory epithelium. We have purified to apparent homogeneity a soluble pyrazine odorant binding protein that constitutes approximately equal to 1% of the total soluble protein in bovine nasal epithelium. Polyacrylamide gel electrophoresis shows a single band of 19,000 Da and gel filtration data suggest that the native protein is a dimer of 38,000 Da. Binding of [3H]IBMP to the purified protein reveals two binding sites (Kd = 10 X 10(-9) M, Bmax = 135 pmol per mg of protein; Kd = 3 X 10(-6) M, Bmax = 25 nmol per mg of protein). The binding affinities of a homologous series of pyrazine odorants correlate with the human odor detection thresholds of these compounds. This correlation, together with the regional distribution of the protein, suggests that the protein is a physiologically relevant olfactory receptor.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Binding Sites
  • Binding, Competitive
  • Cattle
  • In Vitro Techniques
  • Kinetics
  • Male
  • Nasal Mucosa / metabolism*
  • Odorants*
  • Pyrazines / metabolism*
  • Rats
  • Receptors, Cell Surface / isolation & purification*
  • Receptors, Cell Surface / metabolism
  • Tissue Distribution

Substances

  • Pyrazines
  • Receptors, Cell Surface
  • 2-isobutyl-3-methoxypyrazine