AttoPhos® AP Fluorescent Substrate

The AttoPhos® AP Fluorescent Substrate System provides a highly sensitive fluorescent alkaline phosphatase substrate.

The system includes AttoPhos® Substrate, AttoPhos® Buffer and Calibration Solution. AttoPhos® Substrate (2′-[2-benzothiazoyl]-6′-hydroxybenzothiazole phosphate [BBTP]) is cleaved by alkaline phosphatase to produce inorganic phosphate (Pi) and the alcohol, 2′-[2-benzothiazoyl]-6´-hydroxybenzothiazole (BBT). This enzyme-catalyzed conversion of the phosphate form of AttoPhos® Substrate to BBT is accompanied by an enhancement in fluorescence properties.

Relative to AttoPhos® Substrate, BBT has greatly increased quantum efficiency and fluorescence excitation and emission spectra that are shifted well into the visible region. Relative to other fluorometric reporters, the BBT anion has an unusually large Stokes’ shift of 120nm, which leads to lower levels of background fluorescence and higher detection sensitivity.


AttoPhos® AP Fluorescent Substrate Features & Benefits:

• Sensitivity - Low fluorescence signal until enzymatically acted upon, yielding detection of AP to 0.1 attomole.
• Low Background - Low fluorescence from interfering biological molecules.
• Linearity - Linear kinetics over five orders of magnitude of AP concentration.
• Additional Features - Excitation at 435nm, emission at 555nm and large Stokes' shift (≈120nm).