Kinetics of binding of [(3)H]glycine to transport proteins in channel catfish brain.
[(3)H]Glycine was observed to bind to channel catfish brain particles in a manner displaying saturation kinetics. The dissociation constant was calculated to be 7.38 +/- 2.11 microM. Though some binding occurred in the absence of Na(+) ions, the presence of such ions stimulated binding in a concentration-dependent manner. Similarly, chloride ions had a stimulatory effect on [(3)H]glycine binding. Several inhibitors of binding were identified, the most effective being beta-alanine, pipecolic acid, 2,3-pyrazine dicarboxylic acid and 3,5-pyrazole dicarboxylic acid. Each is a structural analogue of glycine. Harmaline, a known inhibitor of Na(+) binding, also inhibited glycine binding. A previous study had shown the presence of a sodium-dependent, active uptake system for glycine in synaptosomes derived from catfish brain. The present results suggest that the binding of [(3)H]glycine was to a glycine transporter and that the amino acid functions as a neurotransmitter in this species.
Achterhof
Rebeca A
RA
Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Evansville, IN 47712, USA.
Tunnicliff
Godfrey
G
D026921:Amino Acid Transport Systems, Neutral / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002712:Chlorides / Q000494:pharmacology; D005998:Glycine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D050487:Glycine Plasma Membrane Transport Proteins; D007059:Ictaluridae / Q000378:metabolism*; D007700:Kinetics; D008024:Ligands; D011869:Radioligand Assay; D012964:Sodium / Q000494:pharmacology; D013574:Synaptosomes / Q000378:metabolism; D014316:Tritium
D026921:Amino Acid Transport Systems, Neutral; D002712:Chlorides; D050487:Glycine Plasma Membrane Transport Proteins; D008024:Ligands; D014316:Tritium; D012964:Sodium; D005998:Glycine