Preparation and use of a cyclodextrinase for preparing maltooligosaccharides

A process for producing maltooligosaccharides which comprises catalytically acting a cyclodextrinase enzyme (EC 3.2.1.54) having the following physicochemical characteristics on cyclodextrins

• wherein the enzyme cleaves cyclodextrins to produce maltooligosaccharides corresponding to the polymerization degree of glucose of the cyclodextrins;
• the hydrolysis rate or affinity of said enzyme for cyclodextrins being higher than that of polysaccharides or linear maltooligosaccharides with the same polymerization degree of glucose as cylodextrins;
• when .alpha.-cyclodextrin is the substrate, Km=0.71;
• when .gamma.cyclodextrin is the substrate, Kn=1.43;
• and
• when .beta.-cyclodextrin is used as a substrate, Km=0.38, the optimum pH of said enzyme is around 8.0 and the stable pH range is 5.5-9.5;
• the working temperature of the enzyme is around 40.degree. C.;
• the enzyme is substantially inactivated by a treatment at a temperature of 50.degree. C. or more for a period of 15 minutes;
• the enzyme is inhibited by at least 90% by Hg.sup.2+, Cu.sup.2+, Zn.sup.2+, Ni.sup.2+, and Fe.sup.2+ and activated 10-30% by Ca.sup.2+ and Mg.sup.2+ ;
• and
• the molecular weight of the enzyme is 144,000 when measured according to gel filtration method and 72,000 when measured according to SDS PAGE method.