BRS1, a C30 bis-amino, bis-hydroxy polyunsaturated lipid from an Australian calcareous sponge that inhibits protein kinase C.

In the course of screening for activity at the phorbol ester binding site of protein kinase C, activity was identified within an unidentified calcareous sponge (class Calcarea) collected in the central region of the Great Barrier Reef off the north-east coast of Australia. Using high-performance liquid chromatographic fractionation guided by activity at the enzyme, the C30 polyunsaturated lipid was isolated and its structure assigned on the basis of spectroscopic analysis. The compound was given the trivial name BRS1. It exhibited a 50% effective concentration for inhibiting phorbol ester binding of 9 microM and for inhibiting enzymic activity of 98 microM. This compound represents a novel protein kinase C inhibitor.