Quantitative determination of phosphoserine by high-performance liquid chromatography as the phenylthiocarbamyl-S-ethylcysteine. Application to picomolar amounts of peptides and proteins.
A method is described that permits the phosphoserine content of proteins and peptides to be determined in picomolar amounts. A micro-batch reaction first converts phosphoserine into S-ethylcysteine. Hydrolysis with 6 M hydrochloric acid then yields the free amino acid, which is coupled with phenyl isothiocyanate to give the corresponding phenylthiocarbamylamino acid. This derivative is determined quantitatively in the range 10-20 pmol by reversed-phase high-performance liquid chromatography. The method works well with either small peptides or proteins in the low picomole range.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000031:analogs & derivatives; D007202:Indicators and Reagents; D009842:Oligopeptides / Q000032:analysis; D010455:Peptides / Q000032:analysis; D010766:Phosphorylation; D010768:Phosphoserine / Q000032:analysis*; D011506:Proteins / Q000032:analysis; D012694:Serine / Q000031:analogs & derivatives*; D014336:Troponin / Q000032:analysis
D000596:Amino Acids; D007202:Indicators and Reagents; D009842:Oligopeptides; D010455:Peptides; D011506:Proteins; D014336:Troponin; C053248:phenylthiocarbamyl-S-ethylcysteine; D010768:Phosphoserine; D012694:Serine; C037642:kemptide; C026826:S-ethylcysteine; D003545:Cysteine