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K G Standing

Publications and source records attributed to K G Standing.

39 records · Page 3Linked to original sources
PubMed1986

Automated dry fraction collection for microbore high-performance liquid chromatography-mass spectrometry.

A method is presented for the collection of dry fractions from a microbore high-performance liquid chromatographic column. These fractions are electrosprayed onto a foil strip that is being moved past the spray in steps. These solid deposits are in a form which is compatible with solid-phase secondary-ion mass spectrometry, in particular the time-of-flight instrument that has been developed in our laboratory. Because the type of ionization used in static secondary-ion spectrometry is essentially non-destructive, the non-volatile eluent is available for any other analytical method after mass analysis. The chromatogram of a mixture of peptides was re-constructed from the mass spectra of fractions collected in this way. This chromatogram is shown and its features are examined.

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Natural peptides as building blocks for the synthesis of large protein-like molecules with hydrazone and oxime linkages.

Methods are known for the production of synthetic protein-like molecules of nonlinear architecture with molecular masses in the 10-20 kDa range. To synthesize such compounds of higher molecular mass and complexity, chemoselective ligation of natural (as opposed to synthetic) peptide building blocks was studied. In preliminary experiments with model peptides, conditions for the formation of peptide oximes were investigated, and their stability at alkaline pH was examined, to resolve a literature controversy. It was found that low pH (down to 2.1) was suitable for polyoxime formation and that the oxime bond was stable for up to 65 h at pH 8 and for more than 2 h at pH 9. Then, using natural peptides, it was found to be possible to synthesize, and characterize by mass spectrometry, nine-component species with molecular masses > 48 kDa. This is about twice the size of homogeneous artificial proteins previously described. Such complex molecules of defined structure are beginning to find applications as vaccine candidates, as radioimmunodiagnostic agents, and as nonviral gene therapy delivery vehicles.

Chromatography, High Pressure Liquid↗