Use of borane as reducing agent in sequence analysis of peptides by gas chromatography-mass spectrometry

Abstract

The properties of borane as a reducing agent for N-acylated peptides, as compared to the known lithium aluminium deuteride procedure have been investigated The resulting polyamino-alcoholds are converted into the corresponding trimethylsilyl ethers and submitted to capillary gas chromatography. With borane the esterification of carboxy groups is not required, reduction proceeds very fast and work-up of the reaction mixture is simple. Correspondingly complete derivatization is caried out in a significantly shorter time than with lithium aluminum deuteride. In addition, fewer side-products are formed, even if a very large excess of borane is used. No problems arise with labile peptides, and the yields are high enough to allow derivatization, separation and identification of peptides in amounts as low as 200 pmoles.The separation of the polyamino-alcohols by capillary gas chromatography was demonstrated, and proved to be superior to the packed columns used hitherto.