SUCH HYDROPHOBIC PEPTIDES AS DANSYLATED MASTOPARAN CAN ELEVATE THE FERTILIZATION MEMBRANE OF SEA-URCHIN EGGS

Melittin is known to be a major hydrophobic peptide component in honey bee venom that can cause as much elevation of fertilization membrane o f sea urchin eggs as normal fertilization. The action of melittin has been thought to be closely related with its ability to facilitate the phospholipase A(2) activity on the eggs. However, another peptide ''ma stoparan'' from wasp venom was not found here to cause any elevation o f the membrane, although it can activate the enzyme as well as melitti n. On the other hand, mastoparan was found to get the membrane-elevati ng activity only when its amino groups were modified with hydrophobic substituents. N-epsilon-Substituted mastoparan with a dansyl group in Lys(11) residue was most effective among the analogs examined here. Ou r findings indicate that the facilitation of phospholipase by the pept ides have little relation with the membrane generation. Such hydrophob ic moiety as the dansyl group in the peptides must cause the cortical reaction on the eggs in cooperation with peptide moiety. The dansylate d peptide will be a useful tool to induce the artificial fertilization of sea urchin eggs. (C) 1995 Academic Press, Inc.