HUYBRECHTS, R.; MACOURS, N.; HENS, K.; VANDINGENEN, A.: Zinc metalloprotease action in insect follicular developement

In mammals, the prominent enzymes involved in regulation of blood pressure homeostasis, namely the carboxydippetidase angiotensin converting enzyme and the endopeptidase endothelin converting enzyme, both act by use of specific substrates.

In insects, the occurrence of these two functional enzymes is demonstrated and further evidenced by cloning of the corresponding gene homologs. Apart from the demonstration of the hydrolyzing activity of circulating ACE upon the oostatic ovarial peptide Neb-TMOF no other putative in vivo substrate revealing specific functioning is reported. In fleshflies, vitellogenic follicles contain a variety of peptides which all are high affinity substrates of ACE and which individually align to N-terminal yolk polypeptide sequences.

We are presently exploring in fleshflies the in mosquitoes described accumulation of ACE in vitellogenic follicles as well as the universality of ovarial ECE as observed in grasshoppers. If both positive, these observations might indicate a primary role for both ACE and ECE in mobilization of amino acids from accumulated storage proteins, in casu the vitellogenins.