Glycoside hydrolase family 7
Encyclopedia
In molecular biology, glycoside hydrolase family 7 is a family
of glycoside hydrolases
.
Glycoside hydrolases are a widespread group of enzymes that hydrolyse the glycosidic bond
between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycoside hydrolases, based on sequence similarity, has led to the definition of >100 different families. This classification is available on the CAZy(http://www.cazy.org/GH1.html) web site, and also discussed at CAZypedia, an online encyclopedia of carbohydrate active enzymes.
Glycoside hydrolase family 7 CAZY GH_7 comprises enzymes with several known activities including endoglucanase and cellobiohydrolase . These enzymes were formerly known as cellulase family C.
Exoglucanases and cellobiohydrolases play a role in the conversion of cellulose
to glucose
by cutting the disaccharide
cellobiose
from the non-reducing end of the cellulose polymer chain. Structurally, cellulases and xylanases
frequently consist of a catalytic domain joined to a cellulose-binding domain
(CBD) via a linker region that is rich in proline
and/or hydroxy-amino acids. In type I exoglucanases, the CBD domain is found at the C-terminal extremity of these enzyme (this short domain forms a hairpin loop structure stabilised by 2 disulphide bridges).
Protein family
A protein family is a group of evolutionarily-related proteins, and is often nearly synonymous with gene family. The term protein family should not be confused with family as it is used in taxonomy....
of glycoside hydrolases
Glycoside hydrolase
Glycoside hydrolases catalyze the hydrolysis of the glycosidic linkage to release smaller sugars...
.
Glycoside hydrolases are a widespread group of enzymes that hydrolyse the glycosidic bond
Glycosidic bond
In chemistry, a glycosidic bond is a type of covalent bond that joins a carbohydrate molecule to another group, which may or may not be another carbohydrate....
between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycoside hydrolases, based on sequence similarity, has led to the definition of >100 different families. This classification is available on the CAZy(http://www.cazy.org/GH1.html) web site, and also discussed at CAZypedia, an online encyclopedia of carbohydrate active enzymes.
Glycoside hydrolase family 7 CAZY GH_7 comprises enzymes with several known activities including endoglucanase and cellobiohydrolase . These enzymes were formerly known as cellulase family C.
Exoglucanases and cellobiohydrolases play a role in the conversion of cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
to glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
by cutting the disaccharide
Disaccharide
A disaccharide or biose is the carbohydrate formed when two monosaccharides undergo a condensation reaction which involves the elimination of a small molecule, such as water, from the functional groups only. Like monosaccharides, disaccharides form an aqueous solution when dissolved in water...
cellobiose
Cellobiose
Cellobiose is a disaccharide with the formula [HOCH2CHO3]2O. Cellobiose consists of two glucose molecules linked by a β bond. It can be hydrolyzed to glucose enzymatically or with acid. Cellobiose has eight free alcohol groups, one acetal linkage and one hemiacetal linkages, which give rise to...
from the non-reducing end of the cellulose polymer chain. Structurally, cellulases and xylanases
Xylanase
Xylanase is the name given to a class of enzymes which degrade the linear polysaccharide beta-1,4-xylan into xylose, thus breaking down hemicellulose, one of the major components of plant cell walls....
frequently consist of a catalytic domain joined to a cellulose-binding domain
Carbohydrate-binding module
In molecular biology, a carbohydrate-binding module is a protein domain found in carbohydrate-active enzymes . The majority of these domains have carbohydrate-binding activity. Some of these domains are found on cellulosomal scaffoldin proteins. CBMs were previously known as cellulose-binding...
(CBD) via a linker region that is rich in proline
Proline
Proline is an α-amino acid, one of the twenty DNA-encoded amino acids. Its codons are CCU, CCC, CCA, and CCG. It is not an essential amino acid, which means that the human body can synthesize it. It is unique among the 20 protein-forming amino acids in that the α-amino group is secondary...
and/or hydroxy-amino acids. In type I exoglucanases, the CBD domain is found at the C-terminal extremity of these enzyme (this short domain forms a hairpin loop structure stabilised by 2 disulphide bridges).