Glycosidases classification

Boehringer Mannheim metabolic chart Biocatalysis/Biodegradation DB (BBD) Glycosidase classification ... 

Fig. 4. syn- and anti-protonation, respectively, of 0-1 as a means of classification of glycosidases. 

W. W. Pigman, Specificity, classification and mechanism of action of the glycosidases, Adv. Enzymol. Relat. Subj. Biochem., 4 (1944) 41—74. 

Many glycosidases which attack insoluble or partly soluble polysaccharides have a modular construction, in which catalytic domains and carbohydrate binding modules (CBMs) are produced in the same polypeptide. Although there may be occasional exceptions, the main function of these domains appears to be to increase the local concentration of enzyme by loosely absorbing the enzyme to the substrate. CBMs have been classified into families on the basis of amino acid sequence, like the catalytic domains and are on CAZy, the continuously updated website in summer 2007 there were 49 families. Early work had concentrated on the cellulose binding domains (CBDs) previous classifications had referred to CBM (or CBD) Types and used Roman numerals and, to concur with this usage, CBM Families 1-13 are the same as CBM Types 1-XIII. 

A new classification of glycosidases was introduced by Bernard Henrissat in 1991, based on the premise that the primary sequences of proteins dictate their three-dimensional structures and hence their catalytic... 

Carbohydrates constitute one the of most complex structures occurring in nature (with nucleic acids and proteins) due to i) the monosaccharide diversity, ii) the type of linkage and iii) the nature of carbohydrate-linked molecules. As a result, GHs present a wide range of activities, which have necessitated the creation of a specific classification more explicit than the lUB Enzyme Nomenclature. In 1998, the Carbohydrate-Active Enzymes (CAZy) database was created, gathering glycosidases in famiUes based on amino-acid sequence and protein structures similarities. ... 

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