TABLE 2.
Characteristics of C. tropicalis-secreted aspartic proteinases
| Characteristic | Result for aspartic proteinase
|
|||
|---|---|---|---|---|
| Sapt1p | Sapt2p | Sapt3p | Sapt4p | |
| Preproprotein length (amino acids) | 394 | 415 | 389 | 394 |
| Mature domain of the protein (amino acids) | 334 | 341 | 338 | 342 |
| Putative KR processing site (amino acid positions) | 32–33, 59–60 | 38–39, 73–74 | 50–51 | 51–52 |
| Theoretical molecular mass of the polypeptide domain of the mature domain (kDa)a | 35.8 | 36.5 | 37.1 | 37.4 |
| Apparent molecular mass determined by SDS-PAGE (kDa) | 44 | 49 | 48/55b | NDc |
| Apparent molecular mass after N-glycosidase treatment by SDS-PAGE (kDa) | 44 | 40 | 44/50b | ND |
| No. of putative glycosylation sites | 0 | 4 | 2 | 5 |
| Calculated pIa | 4.23 | 4.09 | 4.95 | 5.69 |
| Optimum pH of activity experimentally determined | 3.5 | 5.0 | 5.0 | ND |
a
The theoretical molecular mass of the mature domain and the pI were calculated with the program Compute pI/Mw tool (http://www.expasy.ch/ch2d/pi_tool.html).
b
Mature form and proprotein.
c
ND, not done. (No recombinant SAPT4 translation product was obtained from P. pastoris transformants.)