A procedure for easy removal of acrylamide gel rods from the casting glass tubes |
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Authors: | G D Ghadge A M Bodhe S R Modak H G Vartak |
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Affiliation: | 1. Department of Medical Chemistry, Kyoto University Faculty of Medicine, Kyoto 606, Japan;2. Department of Chemistry, Osaka City University Faculty of Science, Osaka 558, Japan |
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Abstract: | A new method specific for the determination of subpicomole quantities of tryptophan has been developed by elaboration of the Pictet-Spengler reaction. It permitted reproducible quantitation of tryptophan in less than 1 μl of plasma ultrafiltrate or 1 mg of brain tissue. Samples deproteinized by trichloroacetic acid were boiled for 15 min with formaldehyde and potassium ferricyanide at controlled acidity, where tryptophan was converted to a single new product identified as 9-hydroxymethyl-β-carboline. It was quantitated by either direct spectrofluorometry or a reversed-phase HPLC system developed for β-carbolines. Under our conditions, peptides containing N-terminal tryptophan such as Trp-Leu and delta sleep-inducing peptide gave N-(9-hydroxymethyl-β-carboline-3-carbonyl) peptides which retained all amino acid residues except tryptophan. |
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Keywords: | tryptophan β-carbolines tryptophanyl peptides β-carboline peptides picomole analysis fluorometry |
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