Definitions and Terminology in CAZy

Classifications in CAZy : short description

The CAZy database presently describes two types of common components of Carbohydrate-active enzymes:

Catalytic Modules (Enzymes) Subdivided in various enzyme classes and families thereof that catalyze the breakdown, biosynthesis and/or modification of glycoconjugates, oligo- and polysaccharides
Associated Modules Families of modules found attached to the catalytic modules

Family, Subfamily and Clan Acronyms in CAZy : common designations


Families are typically designated using a simple form including the class or category of the module and a number that reflects the order of family creation within the same group. The common designations found in our site are:

Family Extended Designation
GH# Glycoside Hydrolase Family # (ex: GH7)
GT# Glycosyltransferase Family # (ex: GT7)
PL# Polysaccharide Lyase Family # (ex: PL5)
CE# Carbohydrate Esterase Family # (ex: CE2)
CBM# Carbohydrate-Binding Module Family # (ex: CBM35)


Subfamilies are subgroups found within a family that share a more recent ancestor and, that are usually more uniform in molecular function. At present, subfamilies where originally described for family GH13 and now also cover all PL families. Subfamily assignments are gradually being extended to other CAZy families. Each subfamily is designated by a numeral suffix as follows:

Subfamily Extended Designation
GH#_[1,2,3,...,n] Glycoside Hydrolase Family #, Subfamily [1,2,3,...,n] (ex: GH13_1)


Clans are groups of families sharing a fold and catalytic machinery. They represent a higher level in the hierarchy of CAZy classification and are only defined for Glycoside Hydrolases at present. The common designation is GH-Letter (ex: GH-A) where the letter simply reflects the order of definition of the clans. Attribution of GH families to clans usually follows structural determination.

Last update: 2017-03-07 © Copyright 1998-2017
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