TABLE 3.
Biochemical activities of extracellular chitin depolymerases of M. degradans strain 2-40
| Enzyme | Depolymerizationa of substrate:
|
Enzyme activityb (U/mg) on substrate:
|
||
|---|---|---|---|---|
| Chitin and chitin azure | Glycol chitin | MUF-diNAG | MUF-triNAG | |
| ChiA | + | + | 0 | 0 |
| ChiB | + | + | 7.5 | 0 |
| ChiC | + | + | 12.5 | 31.5 |
a
Depolymerization (+) of chitin and chitin azure as indicated by the appearance of a 2-mm zone of clearing around colonies expressing these enzymes. Depolymerization (+) of glycol chitin was determined using zymogram analysis and purified protein preparations as described in the legend to Fig. 1.
b
E. coli expressing each enzyme and purified enzyme preparations were analyzed with MUF-diNAG and MUF-triNAG. One unit of activity is defined as the number of micromoles of 4′-methylumbelliferone released per minute per milligram of purified enzyme. Activities were assayed as described in Materials and Methods.