This family consists of several bacterial acetyl xylan esterase proteins. Acetyl xylan esterases are enzymes that hydrolyse the ester linkages of the acetyl groups in position 2 and/or 3 of the xylose moieties of natural acetylated xylan from hardwood. These enzymes are one of the accessory enzymes which are part of the xylanolytic system, together with xylanases, beta-xylosidases, alpha-arabinofuranosidases and methylglucuronidases; these are all required for the complete hydrolysis of xylan [1].

1: The acetyl xylan esterase of Bacillus pumilus belongs to a family of esterases with broad substrate specificity. Degrassi G, Kojic M, Ljubijankic G, Venturi V; Microbiology 2000;146:1585-1591. PMID:10878123