endo-1,3-ò-Xylanase, [xylanase (ambiguous), endo-1,3-ò-xylosidase, 1,3-ò-xylanase, 1,3-xylanase, ò-1,3-xylanase, endo-ò-1,3-xylanase, 1,3-ò-<small>D</small>-xylan xylanohydrolase, xylan endo-1,3-ò-xylosidase (misleading)] is an enzyme with systematic name 3-ò-<small>D</small>-xylan xylanohydrolase. It catalyses the following chemical reaction:
The enzyme is found mostly in marine bacteria, which break down the ò(1,3)-xylan found in the cell wall of some green and red algae. It produces mainly xylobiose, xylotriose and xylotetraose.