Interaction of beta-cyclodextrin with the granular starch binding domain of glucoamylase.
The granular starch binding domain of glucoamylase 1 (EC 3.2.1.3 1,4-alpha-D-glucan glucohydrolase) binds two molecules of beta-cyclodextrin, with a dissociation constant (Kd) for the second ligand of 1.68 microM. The catalytic domain showed no interaction with beta-cyclodextrin. Beta-cyclodextrin competitively inhibited the adsorption of the binding domain onto granular starch with an inhibition constant (Ki) of 11.0 +/- 1.9 microM. The results show that beta-cyclodextrin binds to the binding domain of glucoamylase at the same site(s) as granular starch.
Belshaw
N J
NJ
AFRC Institute of Food Research, Norwich, Norfolk, U.K.
Williamson
G
G
D001234:Aspergillus niger / Q000201:enzymology; D001665:Binding Sites; D002384:Catalysis; D003505:Cyclodextrins / Q000378:metabolism*; D005087:Glucan 1,4-alpha-Glucosidase / Q000378:metabolism*; D011485:Protein Binding; D013056:Spectrophotometry, Ultraviolet; D013213:Starch / Q000378:metabolism*; D047392:beta-Cyclodextrins
D003505:Cyclodextrins; D047392:beta-Cyclodextrins; D013213:Starch; D005087:Glucan 1,4-alpha-Glucosidase; C031215:betadex