MONOMER MAPPING - A PC-BASED SOFTWARE TOOL FACILITATING THE DETERMINATION OF MONOMER COMPOSITIONS FROM MASS-SPECTROMETRIC MOLECULAR-WEIGHT DATA

A method has been developed to establish the monomer composition of (bio)macromolecules. The method, which we call monomer mapping, involves mass spectrometry and a computer program. Given the (nominal) m/z value of the molecular ion as well as the elemental compositions of all monomeric residues possibly present, the computer program generates all fitting monomer compositions and their corresponding m/z ratios. The determination of the monomer composition is enabled by verification of the presence of a signal at the calculated m/z ratios for the individual monomers, using high resolving power mass spectrometry. Monomer mapping can be used to determine monomer compositions of individual components in mixtures without applying (chromatographic) separation techniques. The scope of monomer mapping has been enlarged by combining it with the results of per-O-methylation, which gives information on the number of exchangeable hydrogens. The results of, for instance, amino acid analysis could also be included in the program. Monomer mapping has been successfully applied to determine the glycosyl compositions of saponins.