HEMIFISTULARIN-3 - A DEGRADED PEPTIDE OR BIOGENETIC PRECURSOR - ISOLATION FROM A SPONGE OF THE ORDER VERONGIDA FROM THE CORAL SEA OR GENERATION FROM BASE TREATMENT OF 11-OXOFISTULARIN-3

Hemifistularin 3 10, contained in a new species of sponge of the famil y Aplysinellidae, order Verongida, from the Coral Sea, corresponds to the right half of 11-oxofistularin 3 6, also contained in this sponge, and from which it can be obtained in a peculiar base-catalysed degrad ation. This raises the question of whether or not hemifistularin 3 is the first example of a biogenetically degraded peptide, or rather an e laborated biogenetic precursor, in sponges of the order Verongida. The new compounds 19-deoxyfistularin 3 8 and 19-deoxy-11-oxofistularin 3 9 have also been isolated from the same sponge.