Fig. 4

Human meprin α and β are capable of processing VEGF-A specifically.

(A) The cleavage of recombinant human VEGF-A₁₆₅ (CON, untreated, 24 kDa) by recombinant meprin α and β (each 85 nM) for 1 to 30 min resulted in two fragments of different molecular weight (19.6 kDa in case of meprin α, 20.5 kDa by meprin β), visualized by western blot analysis. In wild type zebrafish whole lysates (FL), VEGF-A could be detected using specific antibodies indicating a fragment similar to that produced by meprin processing. (B) Domain structure of human VEGF-A₁₆₅ (P15692-4). The lightning indicates the cleavage site between Ala4 and Glu5, identified after incubation with recombinant human meprin α. PDGF (platelet-derived growth factor). In addition, the N-terminal cleavage site in human VEGF-A₁₆₅ between Ala30 and Glu31 due to recombinant human meprin α activity could be identified by N-terminal sequencing.