Cyclodextrin(CD)is produced by the catalysis of starch or starch derivatives by cyclodextrin glucosyltransferase(CGTase),and its yield is mainly limited by the product and reaction specificity of CGTase.In this study,...Cyclodextrin(CD)is produced by the catalysis of starch or starch derivatives by cyclodextrin glucosyltransferase(CGTase),and its yield is mainly limited by the product and reaction specificity of CGTase.In this study,we use CGTase derived from Bacillus stearothermophilus NO_(2),exhibiting high expression levels and good stability for molecular modification.The N353A mutant effectively decreases the hydrolysis activity,and the ratio of the k_(cat) values(cyclization to hydrolysis activity)is 86.46,which is threefold that of the wild type.The E142P mutant effectively enhancesα-CD specificity,which increases the ratio of k_(cat) values(α-CD toβ-CD formation)from 2.18 of the wild-type to 2.42.The N353A/E142P mutant weakens the hydrolysis side reaction and enhancesα-CD specificity,and the proportion ofα-CD products is 53.67%,which is 15.62%higher than that of the wild-type.This research focuses on CGTase reaction and product specificities,which suggest a novel method for the industrial production ofα-CD.展开更多
基金We thank the National Natural Science Foundation of China(31730067 and 31972032)Agricultural Independent Innovation Fund of Jiangsu Province(CX(21)3039)Postgraduate Research and Practice Innovation Program of Jiangsu Province(KYCX21-2025)for financial supports.
文摘Cyclodextrin(CD)is produced by the catalysis of starch or starch derivatives by cyclodextrin glucosyltransferase(CGTase),and its yield is mainly limited by the product and reaction specificity of CGTase.In this study,we use CGTase derived from Bacillus stearothermophilus NO_(2),exhibiting high expression levels and good stability for molecular modification.The N353A mutant effectively decreases the hydrolysis activity,and the ratio of the k_(cat) values(cyclization to hydrolysis activity)is 86.46,which is threefold that of the wild type.The E142P mutant effectively enhancesα-CD specificity,which increases the ratio of k_(cat) values(α-CD toβ-CD formation)from 2.18 of the wild-type to 2.42.The N353A/E142P mutant weakens the hydrolysis side reaction and enhancesα-CD specificity,and the proportion ofα-CD products is 53.67%,which is 15.62%higher than that of the wild-type.This research focuses on CGTase reaction and product specificities,which suggest a novel method for the industrial production ofα-CD.
