Enzyme diagnostic criteria for polysaccharide purity: A model study using polymer reference standards

Some natural polysaccharides may be purified as mixtures of simpler polymers having close molecular size, and elucidated to have complicated structures. To address this concern, an enzyme diagnostic criteria for polysaccharide purity has been proposed recently. Herein, model studies using polymer reference standards are conducted to test this conception. In this study, five mixture models were designed using qualified reference standards, including xylan, galactan, polygalacturonic acid, arabinoxylan, glucomannan, pullulan, and dextran. These models simulate plausible co-extraction scenarios involving both homopolysaccharides and heteropolysaccharides, and all satisfy current purity standards. Following conventional structural elucidation, these mixtures showed complex and questionable structures. Before testing these models, diagnostic enzymes were selected based on the structural units and were individually validated for substrate efficiency. These enzymes effectively revealed the presence of mixtures in all models by producing significant HPGPC peak shifts after hydrolysis. These findings confirmed the strength and efficiency of the proposed polysaccharide purity criterion.