Table 2.
Minimal concentration of human plasminogen required for NA-mediated polykaryon formation by the HA
| Expressed protein* | Concentration of human plasminogen, μg/ml
|
Trypsin, μg/ml
|
||||
|---|---|---|---|---|---|---|
| 5000 | 500 | 50 | 5 | 0.5 | 0.5 | |
| HA/WSN NA | NT | NT | NT | + | − | + |
| HA/WSN NA− | NT | + | + | + | − | + |
| HA/WSN NA R146N | NT | + | + | − | − | + |
| HA only | − | − | NT | NT | NT | + |
Polykaryon formation was determined as described in the legend to Fig. 2. −, no polykaryon formation; +, 100% polykaryon formation as shown in Fig. 2; NT, not tested.
*
NA− denotes a mutant with loss of NA enzymatic activity due to Glu-to-Gln change at position 227. The R146N mutant possesses a potential glycosylation site at position 146.