N-terminal Early set domain associated with the catalytic domain of cellulase. E or "early" set domains are associated with the catalytic domain of cellulases at the N-terminal end. Cellulases are O-glycosyl hydrolases (GHs) that hydrolyze beta 1-4 glucosidic bonds in cellulose. They are usually categorized into either exoglucanases, which sequentially release terminal sugar units from the cellulose chain, or endoglucanases, which also attack the chain internally. The N-terminal domain of cellulase may be related to the immunoglobulin and/or fibronectin type III superfamilies. These domains are associated with different types of catalytic domains at either the N-terminal or C-terminal end and may be involved in homodimeric/tetrameric/dodecameric interactions. Members of this family include members of the alpha amylase family, sialidase, galactose oxidase, cellulase, cellulose, hyaluronate lyase, chitobiase, and chitinase, among others.

Cellulase N-terminal ig-like domain.

Crystalstructure of metagenome-derived glycoside hydrolase family 9 endoglucanase [uncultured bacterium],3X17_B Crystal structure of metagenome-derived glycoside hydrolase family 9 endoglucanase [uncultured bacterium]

Crystalstructure of GH family 9 endoglucanase J30 [Thermobacillus composti KWC4]