252Cf plasma desorption mass spectrometric study of interactions of steroid glycosides with amino acids

252Cf Plasma desorption with time-of-flight mass spectrometry (TOF-PDMS) has been applied to comparative studies of the interactions of steroid glycosides (SGs) of the spirostan series with amino acids. SGs can interact with amino acids to form heteroclusters of the type SG + aminoacid + H](+) and SG + aminoacid + K](+). It is shown how the affinity of SGs for amino acids depends on the structures of both the SG carbohydrate chain and the SG aglycone, and on the nature of the amino acid side chain. Copyright 2000 John Wiley & Sons, Ltd.