Cyclodextrin glycosyltransferase
（重定向自Cyclodextrin glucanotransferase）
Cyclodextrin glycosyl transferase (also Cyclodextrin glucosyltransferase or Cyclodextrin glucanotransferase) or CGTase for short (EC2.4.1.19) is a bacterial enzyme belonging to the same family of the α-amylase specifically known as glycosyl-hydrolase family 13. This peculiar enzyme is capable of catalyzing more than one reaction with the most important being the synthesis of non-reducing cyclic dextrins known as cyclodextrins starting from starch, amylose, and other polysaccharides. CGTase is an enzyme common to many bacterial species, in particular of the Bacillus genus (e.g. B. circulans, B. macerans and B. stearothermophilus), as well as to some archaea, but it is not known to be present in any other species.