Glucanases (Gase) are enzymes which break down glucans which are part of plant cell wall.  Gase hydrolyzes the 1,4-β-glycosidic link in cellulose, lichenin and β-D-glucan. 
- Endo-Gase breaks internal cellulose bonds[1]. 
 - Exo-Gase cleaves 2 to 4 units from the ends of exposed cellulose polysaccharide chains[2]. *Xyloglucanase (XGase) breaks down the hemicellulose xyloglucan[3]. 
 - alpha-1,3-glucanase hydrolyzes alpha-1,3-glucan [4]. 
 - beta-1,3-glucanase enhances fungal resistance in plants[5]. 
 
Gase are classified according to polysaccharide bond which they break. For details see 
*Molecular Playground/1,3-1,4-beta-D-glucanase
  *Crystal Structure Determination of Pseudomonas stutzeri A1501 endoglucanase Cel5A
*(1→3)-α-Glucanases: An Alternative to Control Dental Plaque and Improve Oral Health.
 3D structures of glucanase
Glucanase 3D structures