Table I.
Protease | Length (aa) |
Catalytic domain1 |
Mature MW |
Activity3 | Chromo- some |
Exons | Optimal pH |
Activation | Stage Expression | Substrate specificity |
---|---|---|---|---|---|---|---|---|---|---|
TgCPL | 422 | 206–420 | 30 kDa | Endo | Ib | 4 | 5.5–6.0 (polypeptide) 6.5 (synthetic peptides) | Autoactivation in vitro | Tachyzoite and bradyzoite | P2 hydrophobic |
TgCPB | 569 | 275–532 | 28 kDa | Endo/Exo | XII | 7 | ND | Autoactivation in vitro | Tachyzoite and bradyzoite (microarray analysis) | P2 hydrophobic |
TgCPC1 | 733 | 412–709 | 35 kDa2 | Exo | IX | 9 | 6.5 | No autoactivation in vitro | Tachyzoite | 17-fold higher activity for Gly-Arg than human cathepsin-C specific substrate Gly-Phe |
TgCPC2 | 753 | 357–630 | 44 kDa2 | Exo | III | 10 | ND | No autoactivation in vitro | Tachyzoite | ND |
TgCPC3 | 622 | 335–647 | 32 kDa2 | Exo | IX | 14 | ND | ND | Sporozoite (expressed sequence tags) | ND |
Numbered from the initiator methionine.
MW is based on the size of the catalytic domain without further processing into the heavy and light chains, if occurring.
Endo, endopeptidase; Exo, exopeptidase