Highly acidic proteins from human brain: purification and properties of Glu-50 protein.
Three extremely acidic proteins were isolated from human brain and purified to apparent homogeneity. One of them, Glu-50 protein, contained much glutamic acid (about 50% of the total amino acids). Its purification involved ammonium sulfate fractionation, DEAE-Sephadex A-50 chromatography, and gel filtration on Sephadex G-100 and G-75. Its molecular weight was determined to be 11,000 by SDS polyacrylamide gel electrophoresis and 34,000-36,000 by gel filtration on Sephadex G-75, suggesting that it consists of three identical polypeptide chains. Its isoelectric point was pH 3.9. Its N-terminal amino acid sequence was NH2-Asp-Glu-Pro-Pro-Asp-Glu and its C-terminal amino acid was Lys. It contained no detectable carbohydrate.
D000596:Amino Acids / Q000032:analysis; D001923:Brain Chemistry; D055598:Chemical Phenomena; D002621:Chemistry; D002845:Chromatography / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel; D005971:Glutamates / Q000032:analysis*; D018698:Glutamic Acid; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009419:Nerve Tissue Proteins / Q000302:isolation & purification*
D000596:Amino Acids; D005971:Glutamates; D009419:Nerve Tissue Proteins; D018698:Glutamic Acid