Tryptophan binding to nuclei of rat brain.
Nuclei purified from whole rat brain specifically bind [3H]tryptophan ([3H]Trp) under in vitro conditions. Excess unlabeled Trp (10(-4) M) is an effective inhibitor of in vitro [3H]Trp binding to brain nuclei. Rats tube-fed L-tryptophan (Trp) (30 mg/100 g body wt) 30 min to 4 hr before killing revealed decreased specific binding of [3H]Trp to purified brain nuclei in vitro. By Scatchard analysis, the nuclei from whole brain appear to contain one binding site for [3H]Trp, and the KD is 263 nM. A number of Trp-related compounds, Trp metabolites, or other amino acids and their analogues were observed to compete for in vitro [3H]Trp binding to brain nuclei. The ability of Trp analogues, metabolites, and other cognate compounds to inhibit in vitro [3H]Trp binding to brain nuclei was evaluated and utilized to map the active site of Trp binding.
Cosgrove
J W
JW
Department of Pathology, George Washington University Medical Center, Washington, DC 20037.
Verney
E
E
Schwartz
A M
AM
Sidransky
H
H
D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D001923:Brain Chemistry; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D011485:Protein Binding; D051381:Rats; D017207:Rats, Sprague-Dawley; D011956:Receptors, Cell Surface / Q000032:analysis / Q000378:metabolism; D013997:Time Factors; D014316:Tritium; D014364:Tryptophan / Q000378:metabolism*
D011956:Receptors, Cell Surface; D014316:Tritium; D014364:Tryptophan