Kinetic studies of Thermobifida fusca Ce19A active site mutant enzymes

The catalytic mechanism of Thermobifida fusca Ce19A-90 is determined by constructing, cloning and expressing 12 mutant genes with changes in five conserved residues of Ce19A-68 in Escherichia coli. The results revealed the function of E424 as the catalytic acid, requirement of D55 and D58 as catalytic base activity, and important role of Y206 in binding catalysis and processivity, while Y318 is important for binding of crystalline cellulose substrates and is required for processivity.