title: The action pattern of human salivary alpha-amylase in the vicinity of the branch points of amylopectin.
abstract: Salivary alpha-amylase hydrolyses amylopectin in stages. At the end of the so-called second stage, there are present glucose, maltose, and a series of alpha-limit dextrins containing (1 leads to 4)- and (1 leads to 6)-alpha-D-glucosidic bonds. The structures of the limit dextrins containing a single (1 leads to 6)-bond were examined. Six such dextrins were found. Of these, two were capable of being further hydrolysed by alpha-amylase, whereas the remaining four were true, amylase-resistant alpha-limit dextrins. The structures of the limit dextrins afforded information about those (1 leads to 4)-alpha-D-glucosidic bonds of amylopectin that are capable of being cleaved by salivary alpha-amylase and those that are resistant. In order to define further the action of alpha-amylase, the alpha-amylolytic products of 6-alpha-maltotriosyl-D-glucose, 6(3)-alpha-maltotriosylmaltotriose, and 6(3)-alpha-maltotriosylmaltotetraose were examined.
mesh_terms: D000681:Amylases / Q000378:metabolism*; D000687:Amylopectin; D006801:Humans; D012469:Salivary Glands / Q000201:enzymology*; D013379:Substrate Specificity; D000516:alpha-Amylases / Q000378:metabolism*
chemical_list: D000687:Amylopectin; D000681:Amylases; D000516:alpha-Amylases