Tethered phytic acid as a probe for measuring phytase activity.

A novel approach for measuring phytase activity is presented. We have developed a new chromophoric substrate analog of phytic acid, 5-O-[6-(benzoylamino)hexyl]-d-myo-inositol-1,2,3,4,6-pentakisphosphate that permits direct measurement of the phosphate ester bond-cleavage reaction using HPLC. This compound, along with its dephosphorylated T-phosphatidylinositol intermediates, are quantified using reversed phase chromatography with UV detection.