Báo cáo khoa học: nsights into the reaction mechanism of glycosyl hydrolase family 49 Site-directed mutagenesis and substrate preference of isopullulanase

Aspergillus nigerisopullulanase (IPU) is the only pullulan-hydrolase inglycosyl hydrolase (GH) family 49 anddoes not hydrolyse dextran at all, while all other GH family 49 enzymes are dextran-hydrolysing enzymes. To investigate the common catalyticmechanismofGHfamily 49 enzymes, nine mutants were prepared to replace residues conserved among GH family 49 (four Trp, three Asp and two Glu).