Peptides resolution

The product of this peptide resolution is the subjected to matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDTTOF) in the case of 2-DE or electrospray ionization-mass spectrometry (ESI-MS) analysis in the case of HPLC separation. 

Vo, T. U., McGown, L. B. (2006). Effects of G-quartet DNA stationary phase destabilization on fibrinogen peptide resolution in capillary electrochromatography. Electrophoresis 27, 749-756. 

HX-MS at both whole protein and peptide resolutions offers important insights into a protein s dynamic properties in solution through its physicochemical properties. At peptide resolution, HX-MS describes the relative exchange across different regions of the protein, contingent on the acid-stable protease s fragmentation profile (see Section 6.2.2). If high-resolution structures of the protein are available, the output of an HX-MS experiment can be overlaid on the structural model of the protein and represented by a heat map of the protein of interest. 

The principal applications of HX-MS are as a comparative tool for interrogating alternate conformational states of proteins and also in monitoring effects of various perturbations on protein dynamics at peptide resolution in the millisecond and slower timescales. 

The cryptophane is typical of the chiral resolution of methane derivatives (eg, CHFClBr) (146) and the basket-shaped host of Figure 23d exhibits extremely high enantioselectivity for various peptides (144). 

Carboxypeptidases are zinc-containing enzymes that catalyze the hydrolysis of polypeptides at the C-terminal peptide bond. The bovine enzyme form A is a monomeric protein comprising 307 amino acid residues. The structure was determined in the laboratory of William Lipscomb, Harvard University, in 1970 and later refined to 1.5 A resolution. Biochemical and x-ray studies have shown that the zinc atom is essential for catalysis by binding to the carbonyl oxygen of the substrate. This binding weakens the C =0 bond by... 

Bella, J., et al. Crystal and molecular structure of a collagen-like peptide at 1.9 A resolution. Science 266 ... 

The three-dimensional structure of HLA-B27 at 2.1 A resolution suggests a general mechanism for tight peptide binding to MHC. Cell 70 1035-1048, 1992. 

FIGURE 2.1 SEC analysis of a polymeric dextran sample (Mw = 1000) on Superdex peptide HR 10/50. The very high resolution between individual components of the sample is obtained by using two columns in series. Courtesy of T. Andersson. (Reproduced with permission from Amersham Pharmacia Biotech.)... 

For the purpose of high-resolution fractionation, the gel medium must be tailor made to cope with different separation ranges. The Superdex family is designed for the high resolution of peptides and proteins having a molecular mass of 500 to 100,000. Also, Sephacryl media have found wide applicability as a final polishing step in process scale SEC (see Section III,C). 

Superose gel material of Pharmacia Biotech is a highly epichloro-hydrine cross-linked agarose matrix that has a pH range of 3-12 (short term 1-14). Hydrophilic interactions may be noticeable for lipids, peptides, and small aromatic compounds, but such interactions might even improve resolution. Superose medium is available in two different porosities Superose 6 HR 10/ 30 (bead size 13 2 /um maximum pressure 1.5 MPa) and Superose 12 HR 10/30 (bead size 10 2 /um maximum pressure 3.0 MPa). 

A. J. Tomlinson and S. Naylor, Enhanced performance membrane preconcentration-capillary electiophoiesis-mass spectiometry (mPC-CE-MS) in conjunction with transient isotachophoresis for analysis of peptide mixtures, J. High Resolut. Chromatogr. 18 384-386(1995). 

K. Matsuoka, M. Taoka, T. Isobe, T. Okuyama and Y. Kato, Automated high-resolution two-dimensional liquid cliromatographic system for the rapid and sensitive separation of complex peptide mixtures , 7. Chromatogr. 515 313-320 (1990). 

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