TABLE 2.
Comparison of the substrate specificities of NagZ and ExoII
| Substrate | GlcNAc released (nmol/h)a
|
|
|---|---|---|
| NagZ | Exo II | |
| N,N′-Diacetylchitobiose | 0.0 | 0.0 |
| p-Nitrophenyl-β-N-acetyl-d-glucosaminide (1) | 25 | 240 |
| p-Nitrophenyl-β-N-acetyl-d-galactosaminide (2) | 0.8 | 6.9 |
| Activity ratio, (1)/(2) | 31 | 35 |
a
The source of enzyme was toluene-treated intact cells from 1 ml of overnight culture of TP75 containing plasmids expressing the relevant gene. The specific activities of the two enzymes should not be compared since the relative expression of the β-N-acetylglucosaminidase genes from the two plasmids is unknown.