Lichenase

Lichenase (, licheninase, β-(1→4)- D -glucan 4-glucanohydrolase, 1,3, 1,4-β-glucan endohydrolase, 1,3, 1,4-β-glucan 4-glucanohydrolase, 1,3-1,4-β- D -glucan 4-glucanohydrolase) is an enzyme with systematic name (1→3)-(1→4)-β- D -glucan 4-glucanohydrolase. It was named after its activity in on lichenin (a form of mixed-linkage glucan).

Activity
This enzyme catalyses hydrolysis of β-(1,4)- D -glucosidic linkages in mixed-linkage glucans containing both (1,3)- and (1,4)-bonds

Specificity
The best-characterised variant of this of enzyme is Bacillus subtilis lichenase, which is used as a molecular biology tool in determining the structure of mixed-linkage glucans. This variant cleaves (1,4) bonds that immediately follow a (1,3) bond.

Other lichenases have different specificities, for example Aspergillus japonicus lichenase cleaves (1,4) bonds that immediately precede a (1,3) bond.

Structure
Lichenases are from glycoside hydrolase family 16, and share a jellyroll structure. A deep surface cleft acts as the substrate binding site.