Strong cation exchange, SCX

This multidimensional protein identification technology (MudPIT) specifically incorporates a strong cationic exchange (SCX) column in tandem with an RP column to achieve maximal resolution and exquisite sensitivity. MudPIT is effective for studying complex proteomes such as mammalian cellular samples. It has been applied to large-scale protein characterization with identification of up to 1484 proteins from yeast in a single experiment.12... 

Aminopropyl silica gel Cyanopropyl silica gel Strong cation exchanger (SCX)... 

Fig. 4.10 Calibration curves for ICSn (R=butyl, phenyl, c-hexyl) separated by HPLC-GFAA with strong cation exchange (SCX) columns using Me0H/H20/NH40Ac eluents are shown with respective correlation...

Figure 4.8. MuDPIT platform. The MuDPIT or multidimensional gel protein identification system is an multidimensional liquid chromatography (LC)-based system of separation prior to tandem mass spectrometry (MS/MS). It is not necessary to purify proteins prior MuDPIT, although a reduction in protein complexity by some prior purification is helpful in obtaining interpretable spectra. Protein lysates are digested into peptides that are loaded onto a strong cation exchange (SCX) support. Peptides are sequentially eluted onto a reverse-phase column for a second separation. Eluted peptides from the reverse-phase column are electrosprayed into a tandem mass spectrometer for amino acid sequencing and identification of proteins in the sample.

If, however, the group bonded to silica carries a negative charge, as does the sulphonic acid group of strong-cation exchange (SCX) phases, the effect of... 

An interesting (if not fully understood) phenomenon has been observed by Smith et al. as strong cation-exchange (SCX) phases were used to separate tricyclic antidepressants [47], A certain focusing effect, which is not reproducible, produced peaks of staggering efficiencies, millions of plates per meter, the... 

Fig. 13.9 The benefits of strong cation exchange (SCX), solid phase extraction (SPE) clean-up of samples. The reversed phase HPLC-ESI-MS base ion (m/z 200-500) chromatograms of a reduced (zinc/sulfuric acid) extract of Senecio ovatus. (a) Methanolic solubles of the reduced extract and, (b) the SCX SPE of the methanolic solubles of the reduced extract.

Fractionation of proteins by strong cation exchange (SCX) chromatography, followed by IMAC enrichment of phosphopeptides from SCX fractions, led to a comprehensive identification of phosphoproteins of PSD isolated from mouse brain using LC-MS/MS (Trinidad et al. 2006). In this study, phosphorylation site(s) were mapped to 287 proteins from a total of 1,264 unique proteins identified. This translates into a 23% phosphorylation rate, comparable to an expected 33% rate in the general proteome (Johnson et al. 2005). The 287 phosphoproteins were derived from a total of 998 unique phosphorylated peptides, and the phosphorylations were mapped to 723 unique sites. Most of these occurred on serines, to a lesser extent on threonines, and only minimally on tyrosines (Figure 5A). 

Multidimensional protein identification (MudPlT) systems were introduced by the group of Yates [7-8], MudPlT is based on LC>strong cation exchange (SCX) column as the first dimension, RPLC as the second dimension, ESl-MS-MS under DDA operation, and subsequent SEQUEST database searching. 

Polyphenolic compounds can interfere in the analysis of red wines, and amino acids in the analysis of grape juices. Consequently several methods for isolating biogenic amines from wines and juices have been proposed liquid-liquid extraction with butanol of the sample preliminarily concentrated and adjusted to pH 1.5 (Almy et al, 1983) in general, for SPE is preferred strong cation exchange (SCX) under... 

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