GH44

GH44 is a glycoside hydrolase family (GH) classified in the CAZy database. Members of GH44 are enzymes that hydrolyze glycosidic bonds in carbohydrate substrates and are principally linked to the degradation of cellulose and related beta-glucans in certain bacteria and fungi. The family contributes to natural biomass turnover and, in some species, participates in cellulosome-like multienzyme complexes.

Enzymes in GH44 typically function as endo-acting cellulases, cleaving internal beta-1,4-glucosidic linkages within glucan chains. Their substrate scope can include soluble cello-oligosaccharides and, in some cases, crystalline cellulose, with varying efficiency across different enzymes. Individual GH44 members show diversity in their optimal temperature and pH, reflecting adaptation to their native environments. In biotechnology, GH44 enzymes are explored for inclusion in enzyme cocktails aimed at lignocellulosic biomass conversion.

Catalysis in GH families generally involves catalytic acidic residues such as aspartate or glutamate, and GH44 enzymes follow this pattern with variations among members. The precise catalytic mechanism (retaining versus inverting) and the details of the active-site architecture can differ within the family, and structural data from several GH44 enzymes have aided substrate understanding without defining a single representative structure for the entire family.

Discovery and classification of GH44 reflect sequence similarity and conserved motifs used by CAZy to group related enzymes. Members are found in bacteria and fungi and are of interest for ecological cellulose degradation as well as industrial applications in biomass processing and biofuel development.