Abstract
The action of cyclization of Bacillus macerans cyclodextrin glucanotransferase (BME) was studied by use of various kinds of surfactants. And it was elucidated by use of reducing end labelled maltosaccharidesthat cyclization proceeds from the non-reducing end of α-1, 4 glucan. Surfactants which have straight carbon chains as hydrophobic moiety were extremely effective in promoting the enzyme action forming α-cyclodextrin (α-CD). On the other hand, surfactants which have more bulky hydrophobic moiety than straight carbon chains were extremely effective for β-CD formation (β-CD forming surfactants). By use of the dextrin, which was prepared from defatted waxy corn starch by the treatment with bacterial liquefying α-amylase and β-amylase and from which only traces of CDs were formed by the action of BME without sodium lauryl sulfate (SDS), the enzyme action was changed so as to form mainly α-CD with α-CD forming surfactants and mainly β-CD with β-CD forming surfactants . And therate of α-CD formation from soluble starch in addition of SDS was 1.6 times as reference (without SDS). Hydrolyzing activity was effectively depressed by the addition of SDS. From these results the authors infer that cyclization proceeds on 65-helices, 76-helices to form a and β-CD from the non-reducing end of α-l, 4 glucans and so that the action pattern of BME depends not only on the specificity of the enzyme itself, but also on the conformation of the substrate as modified by helicogenic complexing agents .
