Which of the following is not a technique for protein precipitation?
(A) Trichloroacetic acid (B) Heat precipitation (C) Isoelectric point method (D) Titration with reducing sugar
(D) Ans: D. Titration with reducing sugar(Ref Harper 30/e p26)Titration with reducing sugar is not used for protein precipitation.Protein precipitation:Widely used to concentrate proteins & purify them from various contaminants.Used for isolating specific protein in quantities sufficient for analysis.Requires multiple successive purification techniques.Classic approaches:Based on,Isoelectric precipitation - Differences in relative solubility of individual proteins as pH function.Precipitation with ethanol or acetone - Polarity.Salting out with ammonium sulfate.Paper chromatography including TLCD.