Table 3. Biochemical characterization of the variants expressed in COS cells.
| Peptide forms | ||||||
|---|---|---|---|---|---|---|
| Location | ||||||
| Variant | Intracellular proteolysed | Extracellular single-chain | ER | Lysosomes | Enzyme activity* (fold increase) | Group† |
| Wild-type | + | + | − | + | 8 (14)‡ | 1 |
| H72L | + | + | − | + | 1 (1)‡ | 1 |
| D196E§ | + | + | − | + | 1 | 1 |
| D196N§ | + | + | − | + | 1 | 1 |
| R220H∥ | + | + | − | + | 1.5 (1.5–2)‡ | 1 |
| F320L∥ | + | + | − | + | 3–4 (1)‡ | 1 |
| T335P | − | − | + | − | 1 | 2 |
| P356R | − | − | + | − | 1 | 2 |
| E402K | + | + | − | + | 3–4 | 1 |
| W714R | − | − | + | − | 1 | 2 |
| R750W | − | − | + | − | 1 | 2 |
| L809P | − | − | + | − | 1 | 2 |
| Del(256–260) | − | − | + | − | 1 | 2 |
| Del(339–342) | − | − | + | − | 1 | 2 |
* Activity relative to mock-transfected cells.
† Group 1 is defined as being transported to the lysosomes, whereas group 2 is accumulating in the ER.
‡ In CHO cells.
§ Substitution of the active-site nucleophile.
∥ Bovine mutations introduced into human LAMAN.