Bis-(4-methylumbelliferyl) phosphate as a substrate for the surface membrane-associated phosphodiesterase activity of pig platelets.

It was found that the newly-available compound, bis-(4-methylumbelliferyl) phosphate, could be used as a substrate for the pig platelet surface membrane-associated phosphodiesterase activity, usually assayed with bis-(p-nitrophenyl) phosphate. This enzyme activity is distinct from the phosphodiesterase activity towards 5'-dTMP-P-nitrophenyl ester, which is probably associated with intracellular membrane structures in platelets. Consequently, the use of the 4-methylumbelliferyl derivative as substrate for the phosphodiesterase activity provides a sensitive, fluorimetric assay for this marker enzyme of the platelet surface membrane.