title: Use of p-aminobenzoic acid and tritiated cyanoborohydride for the detection of pyruvoyl residues in proteins.
abstract: A procedure for the detection of covalently bound pyruvic acid in purified proteins or in crude extracts is described. The dialyzed sample is first treated with sodium cyanoborohydride to reduce any Schiff bases present and then incubated with p-aminobenzoic acid and sodium [3H]cyanoborohydride. Derivatized proteins are visualized by fluorography following sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Gel slices containing the labeled proteins are hydrolyzed, and, after removal of polyacrylic acid, the hydrolysate is subjected to ion-exchange high-performance liquid chromatography. The presence of pyruvic acid is established by the detection of a tritiated, 280-nm absorbing compound with a retention time corresponding to that of synthetic N-(p-carboxyphenyl)alanine. The procedure is capable of detecting protein-bound pyruvic acid in the picomolar range and is easily modified to screen for other covalently bound keto acids.
mesh_terms: D010129:4-Aminobenzoic Acid; D001894:Borohydrides; D002851:Chromatography, High Pressure Liquid; D006640:Histidine Decarboxylase / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D011506:Proteins / Q000032:analysis*; D011773:Pyruvates / Q000032:analysis*; D019289:Pyruvic Acid; D014316:Tritium
chemical_list: D001894:Borohydrides; D011506:Proteins; D011773:Pyruvates; D014316:Tritium; D019289:Pyruvic Acid; C009282:sodium cyanoborohydride; D006640:Histidine Decarboxylase; D010129:4-Aminobenzoic Acid