Methods for structural characterization of the products of cellulose- and xyloglucan-hydrolyzing enzymes

Structural characterization of oligosaccharide products generated by enzymatic hydrolysis of plant cell wall polysaccharides provides valuable information about the enzyme's activity and substrate specificity. In this chapter, we describe some of the chemical, chromatographic, and spectroscopic methods that we routinely use to isolate and characterize oligosaccharides formed by enzymatic fragmentation of cellulose and xyloglucan. These include techniques to determine glycosyl residue and glycosyl linkage compositions by gas chromatography and mass spectrometry. We also illustrate the use of electrospray ionization with multistage mass spectrometry, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and nuclear magnetic resonance spectroscopy to perform detailed structural analysis of these oligosaccharides.