In molecular biology, glycoside hydrolase family 77 is a family

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...

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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.

The enzymes in this family have amylomaltase or 4-α-glucanotransferase activity CAZY GH_77, they transfer a segment of a (1,4)-alpha-D-glucan to a new 4-position in an acceptor, which may be 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...

or (1,4)-alpha-D-glucan. They belong to the disproportionating family of enzymes.