Action of xylan deacetylating enzymes on monoacetyl derivatives of 4-nitrophenyl glycosides of β-D-xylopyranose and α-L-arabinofuranose

Measurements of esterase activity by enzyme-coupled assays on monoacetates of 4-nitrophenyl beta-D-xylopyranoside and 4-nitrophenyl alpha-L-arabinofuranoside showed that acetylxylan esterases of families 1, 4 and 5 produced by Trichoderma reesei and Penicillium purpurogenum have a strong preference for deacetylation of position 2 in xylopyranosides. The acetylxylan esterases exhibit only weak activity on acetylated arabinofuranosides, with 2-acetate as the best substrate. Acetyl esterases of family 16 produced by the same two fungi deacetylate in xylopyranosides preferentially positions 3 and 4. Their specific activity on arabinofuranosides is also much lower than on xylopyranosides. however, substantially greater than that in the case of typical acetylxylan esterases. (C) 2010 Elsevier B.V. All rights reserved.