A NOVEL METHOD FOR DETERMINATION OF INORGANIC POLYPHOSPHATES USING THE FLUORESCENT DYE FURA-2

A method for determining inorganic polyphosphate, which is based on th e Mn2+-induced quenching of the fluorescence of the calcium indicator fura-2, is described. The effect of Mn2+ ions on fura-2 fluorescence i s gradually abolished in the presence of increasing concentrations of polyphosphate; this allows the quantification both of synthetic polyph osphates and of the naturally occurring polymer isolated from tissues or cells. The described method has some advantages compared to convent ional procedures for detection of polyphosphates based on the metachro matic effect on toluidine blue. It can be applied for the determinatio n of pyrophosphate, tripolyphosphate and other short-chain polyphospha tes not detectable by toluidine blue and it can be used for measuremen t both of pyrophosphatase and exopolyphosphatase activity. (C) 1997 Ac ademic Press.