Abstract: A method of solvent-induced protein precipitation (SIP) for detecting the interaction of ligands with proteins in a complex protein sample. After the equal amount of solvent is added to the protein samples with and without a ligand to denature and precipitate the proteins, the protein abundances in supernatant and/or precipitate in the ligand group and the control group are measured by quantitative technology. The target protein(s) of a ligand is/are determined by comparing the differences of protein abundances in the ligand group and the control group. The affinity between a ligand and its targets can be evaluated by dose dependent experiments. This method does not require the chemical modification of the ligand and has the feature of high specificity. Furthermore, in certain embodiments, the targets identified by SIP method are complementary to those identified by thermal proteome profiling (TPP) method.

Abstract: The present invention relates to phosphopeptide isolation and enrichment, particularly to a highly selective and specific phosphopeptide enrichment method. The method mentioned in the invention is based on the strong interaction between zirconium phosphonate and phosphopeptide. Zirconium phosphonate is immobilized on the surface of matrix for phosphopeptide enrichment. Zirconium phosphonate could be immobilized on chip surface, it can also be immobilized on chromatographic matrix for isolation and purification of phosphopeptides. The method shows high specificity for phosphopeptides, it can be applied to purify and enrich low abundance phosphopeptide from biological samples.

Abstract: The present invention relates to an immobilized titanium ion affinity chromatography material and its preparation and application. Titanium ion is immobilized on solid support by taking advantage of strong interaction between titanium ions and phosphate groups on the solid support. The immobilized titanium ion affinity chromatography material is applied to enrich phosphopeptides. Phosphopeptides are isolated because they retained on the affinity material due to the strong chelating interaction between the immobilized titanium ions and the phosphate groups on the phosphopeptides.

Abstract: The present invention relates to phosphopeptide isolation and enrichment, particularly to a highly selective and specific phosphopeptide enrichment method. The method mentioned in the invention is based on the strong interaction between zirconium phosphonate and phosphopeptide. Zirconium phosphonate is immobilized on the surface of matrix for phosphopeptide enrichment. Zirconium phosphonate could be immobilized on chip surface, it can also be immobilized on chromatographic matrix for isolation and purification of phosphopeptides. The method shows high specificity for phosphopeptides, it can be applied to purify and enrich low abundance phosphopeptide from biological samples.