ISSN:
1432-1351
Keywords:
Olfaction
;
Amino acid
;
Receptor binding
;
Electrophysiology
;
Lobster
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary 1. Biochemical and electrophysiological assays were used to test the hypothesis that the olfactory system of the Caribbean spiny lobster, Panulirus argus, contains populations of chemosensory receptors that are differentially sensitive to the L- and D-stereoisomers of the amino acid alanine. 2. Independent binding sites for L-alanine (dissociation constant (K d ) of 6.6 μM and maximum binding (Bmax) of 16.8 fmole/μg protein) and for D-alanine (K d of 21.6 μM and Bmax of 17.8 fmole/μg protein) were characterized biochemically. The interaction of ligand with each binding site is rapid, reversible and saturable with respect to both time and concentration. 3. Based on a difference of at least 20% in the relative sensitivity of an olfactory receptor cell to alanine enantiomers, 44% and 34% of the 77 neurons tested were classified as L-alanine and D-alanine sensitive, respectively. The relative sensitivity to alanine enantiomers was independent of the concentration tested. Stereoselective receptors are likely for 17 of 20 other amino acids tested. 4. The congruence of biochemical and electrophysiological results leads to the conclusion that the lobster's responses to D- and L-alanine are mediated by receptors specific for each stereoisomer and that the receptors are differentially distributed among receptor cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00213067
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