Table 1 Known PAPP-A mediated IGFBP proteolysis
IGFBP | IGF requirement | Role of PAPP-A | Kinetic efficiency | References |
|---|---|---|---|---|
IGFBP-4 | IGF-II (more efficient) or IGF-I | Cleavage at Met-135 and Lys-136 | High | [63] |
IGFBP-4 | Not required | *Same site | Very low | [63] |
IGFBP-5 | Not required; inhibited by IGF presence | Cleavage at Ser-143 and Lys-144 | High | |
IGFBP-2 | IGF dependent | Cleavage at Gln-165 and Met-166 | Less than IGFBP-4 | [67] |