Activity assay on BMCC and xyloglucan
In contrast to the results obtained from the Cel9B truncation mutants on CMC, PASC, and xylan, constructs M1 and to a lesser extent ΔE9B, both containing CBM4, exhibited a marked increase in enzyme activity when BMCC was used as a substrate. All other truncation mutants, as well as wild type Cel9B, exhibited lower activity on BMCC (Figure 5). Similarly, both mutants M1 and ΔE9B displayed significantly higher activities on xyloglucan than the other constructs, suggesting that CBM4 plays an unknown role for these substrates (Figure 6).