Developed for use as a soluble substrate for the detection of alkaline phosphatase activity in Enzyme Immunoassays (EIA). pNPP is the substrate of choice in high sensitivity alkaline phosphatase-based EIA assays.One pNPP tablet and one Tris buffer tablet are dissolved in deionized water and provide a ready-to-use substrate. Each SIGMAFAST pNPP tablet set yields a solution containing 1.0 mg/ml pNPP, 0.2 M Tris buffer. EIA applications using pNPP may be read in timed assays or stopped with 3N NaOH for delayed readings. SIGMAFAST^™ require only the addition of distilled or deionized water to prepare an active substrate solution. Tablets are individually packaged in foil packets.

SIGMA FAST p-Nitrophenyl phosphate Tablets has been used:

• to quantify non-secreted alkaline phosphatase to monitor differentiation of osteoblast-like cells (SaoS-2)
• to stain murine preosteoblast MC3T3-E1 cells in alkaline phosphatase assay
• as a substrate for ExtrAvidin^® alkaline phosphatase to measure hemoglobin-bound α-synuclein using enzyme-linked immunosorbent assay (ELISA)
• as a substrate for alkaline phosphatase conjugated antibodies for detection in ELISA of abirin toxin

Each tablet set dissolved in 5 mL deionized water yields a ready-to-use buffered solution containing pNPP.

ExtrAvidin is a registered trademark of Merck KGaA, Darmstadt, Germany

SIGMAFAST is a trademark of Sigma-Aldrich Co. LLC