期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：1989
卷号：35
期号：1
页码：71-80
DOI：10.3177/jnsv.35.71
出版社：Center for Academic Publications Japan
摘要：An a-amylase inhibitor was prepared from cranberry bean ( Phaseolus vulgaris ). The α-amylase inhibitor was composed of three different subunits not linked by disulfide bridges and only one of them contained carbohydrate. Although the inhibitor was stable at pH 3 to 7, it was heat labile at pH 3 and 5. Chemical modification of the amino groups and the guanido groups in cranberry bean a-amylase inhibitor molecule resulted in rapid loss of the inhibitory activity, respectively. Oxidation of the tryptophan residues also led to loss of the activity. On the other hand, reductive methylation of the amino groups scarcely affected the activity. The inhibitor was quite resistant to the proteolytic digestions by pepsin and trypsin, while it was relatively susceptible to the action of chymotrypsin.
