Recently, much attention has been paid to studies on nano- and microstructures formed by the self-assembly of cyclodextrins (CDs) in the fields of supramolecular chemistry and material science. CDs can adopt various types of assembly modes in aqueous solution, as well as crystal structures. Channel-type assemblies of γ-CD (γ-CDchannel) formed unique micrometer-sized cubes and rods. By using γ-CDchannel as a host, the inclusion of guest molecules dissolved in oils, which has been believed to be impossible, can be realized. Furthermore, γ-CDchannel showed excellent oil dispersion, and formed organogels in a variety of oils and organic solvents at ambient temperature. This article reviews the formation behavior and function of nano- and microstructures formed by the self-assembly of CDs.
Cyclodextrin (CD) is the common name for cyclic α-1,4-glucans; α-, β- and γ-CD, which are composed of 6, 7, 8 D-glucopyranose units, are well-known. However, most scientists have not recognized large-ring cyclodextrins (LR-CDs) composed of more than 9 D-glucopyranose units until recently, although the existence of LR-CDs containing 9?13 D-glucopyranose units in macrocycle was reported about a half century ago. The characteristics of LR-CDs have been studied for the last quarter century, and they are still relatively new materials. In this minireview, the unique characteristics of LR-CDs, including molecular structure, physicochemical properties and inclusion complex formation ability, are discussed. Preparation and purification methods are also reviewed.
Glucoamylase, glucodextranase, trehalase, and eukaryotic N-glycan processing α-glucosidase I have been identified as exo-acting enzymes that hydrolyze α-1,X-glucosidic linkages from the non-reducing end to produce β-glucose. While the physiological functions of these enzymes are different, they share a catalytic (α/α)6 barrel domain and show many structural similarities. These enzymes, with few exceptions, belong to the glycoside hydrolase families (GHs) 15, 37, and 63 in the CAZy database, and all these enzymes have 2 conserved aspartic or glutamic acid residues in the catalytic domain. The observations led us to consider that the group of GH15, GH37, and GH63 may be designated as a “glucoamylase family.” There are also many hydrolases and phosphorylases structurally related to GH15, GH37, and GH63.