Trypsin, reversed-phase chromatography

FIGURE l.l Hydrophobic interaction and reversed-phase chromatography (HIC-RPC). Two-dimensional separation of proteins and alkylbenzenes in consecutive HIC and RPC modes. Column 100 X 8 mm i.d. HIC mobile phase, gradient decreasing from 1.7 to 0 mol/liter ammonium sulfate in 0.02 mol/liter phosphate buffer solution (pH 7) in 15 min. RPC mobile phase, 0.02 mol/liter phosphate buffer solution (pH 7) acetonitrile (65 35 vol/vol) flow rate, I ml/min UV detection 254 nm. Peaks (I) cytochrome c, (2) ribonuclease A, (3) conalbumin, (4) lysozyme, (5) soybean trypsin inhibitor, (6) benzene, (7) toluene, (8) ethylbenzene, (9) propylbenzene, (10) butylbenzene, and (II) amylbenzene. [Reprinted from J. M. J. Frechet (1996). Pore-size specific modification as an approach to a separation media for single-column, two-dimensional HPLC, Am. Lab. 28, 18, p. 31. Copyright 1996 by International Scientific Communications, Inc.. Shelton, CT.]... 

Fig. 9. Reversed-phase separations of cytochrome c digests obtained with trypsin-modified beads (left) and trypsin-modified monolithic reactor (right) in a tandem with a chromatographic column (Reprinted with permission from [90]. Copyright 1996 Wiley-VCH). Conditions digestion (left curve) trypsin-modified beads reactor, 50 mm x 8 mm i.d., 0.2 mg of cytochrome c, digestion buffer, flow rate 0.2 ml/min, 25 °C, residence time, 15 min (right curve) trypsin immobilized onto molded monolith other conditions the same as with trypsin-modified beads. Reversed-phase chromatography column, Nova-Pak C18,150 mm x 3.9 mm i.d., mobile phase gradient 0-70% acetonitrile in 0.1% aqueous trifluoroacetic acid in 15 min, flow rate, 1 ml/min, injection volume 20 pi, UV detection at 254 nm...

Figure 3- Reversed Phase Chromatography of Trypsinized Cytochrome c Before and After Adsorption to Microcon-SCX. Approximately 250 pg of digest was diluted to a total volume of 500 pi and either injected directly onto column (top) or bound and eluted from Microcon-SCX (below) as described in Methods. Separation was performed with an Amicon, C18-300-10sp (4.6 x 250 mm) using a linear gradient of 5 % ACN to 55 % ACN (0.1 % TFA in DIW) in 20 minutes at 1 ml/min.

Titani, K., Sasagawa, T., Resing, K., and Walsh, K. A., A simple and rapid purification of commercial trypsin and chymostrypsin by reverse-phase high-performance liquid chromatography, Anal. Biochem., 123, 408, 1982. 

Proteins from albumin/immunoglobulin-depleted CSF (see Fig. 4) were digested with trypsin and the resultant peptides fractionated by two rounds of chromatography using cation exchange and reversed phase columns. 

The bottom-up approach differs in that the entire proteome is first digested with trypsin and then the fragments are separated by cation-exchange chromatography followed by reverse phase chromatography84,124. The fragments are then analyzed by mass spectrometry and are used to identify the proteins in the sample. 

High-performance affinity chromatography has recently been reported with trypsin-modified avidin supported on 5 pm silica. While the separations were successful and a wide range of foods were studied, elution times were 80 minutes and ADAM post-column reactions were still required (Hayakawa et al. 2009). However, such affinity columns within a solid-phase extraction (SPE) platform make realistic choices for sample preparation, whereby the biotin can be purified and concentrated prior to reversed-phase HPLC. R-Biopharm has recently developed a commercially available antibody-based immunoaffinity column to bind biotin from aqueous extracts, providing an excellent technique to clean up complex samples. 

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