Table 2.

Characteristics of C. tropicalis-secreted aspartic proteinases

CharacteristicResult for aspartic proteinase
Sapt1pSapt2pSapt3pSapt4p
Preproprotein length (amino acids)394415389394
Mature domain of the protein (amino acids)334341338342
Putative KR processing site (amino acid positions)32–33, 59–6038–39, 73–7450–5151–52
Theoretical molecular mass of the polypeptide domain of the mature domain (kDa)a 35.836.537.137.4
Apparent molecular mass determined by SDS-PAGE (kDa)444948/55b NDc
Apparent molecular mass after N-glycosidase treatment by SDS-PAGE (kDa)444044/50b ND
No. of putative glycosylation sites0425
Calculated pIa 4.234.094.955.69
Optimum pH of activity experimentally determined3.55.05.0ND
  • 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 recombinantSAPT4 translation product was obtained from P. pastoris transformants.)