Glucan 1,4-ñ-maltotetraohydrolase (, exo-maltotetraohydrolase, 1,4-ñ-<small>D</small>-glucan maltotetraohydrolase) is an enzyme with systematic name 4-ñ-<small>D</small>-glucan maltotetraohydrolase. It catalyses the hydrolysis of (1âÂÂ4)-ñ-<small>D</small>-glucosidic linkages in amylaceous polysaccharides, to remove successive maltotetraose residues from the non-reducing chain ends