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Nitric Oxide Synthase Detection System, Fluorimetric

sufficient for 200 reactions

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sufficient for 200 reactions

Quality Level


not available in Japan

shipped in

wet ice

storage temp.


Biochem/physiol Actions

Simple and specific assay for the measurement of free nitric oxide (NO) and nitric oxide synthase (NOS) activity in living cells under physiological conditions. Nitric oxide, formed from the amino acid L-arginine via the action of NOS, is a unique cell signaling molecule that functions as both an intracellular and an extracellular messenger. NO has been implicated in vasodilation, neurotransmission, cytotoxicity, and inflammation.
The standard assay for NOS activity is for solubilized cell-free enzyme preparations such as cell lysates, crude tissue extracts or purified enzymes. It measures the production of radio­labeled citrulline from radiolabeled arginine substrate (Sigma Product No. NOS-1). In contrast, the Fluorometric Cell-Associated NOS Detection System measures intracellular production of NO by a non-radiometric method. Radioisotopes are replaced by a cell-permeable diacetate derivative of 4,5-diaminofluorescein (DAF-2 DA). DAF-2 DA penetrates cells rapidly where it is hydrolyzed by intracellular esterase to DAF-2 that, in turn, reacts with NO produced by NOS to form a fluorescent triazolo-fluorescein. The fluorescent product can be quantitated using an excitation filter at 492 nm and an emission filter at 515 nm.

Legal Information

DAF-2 DA is manufactured by Daiichi Pure Chemicals Co., LTD.
US Patent No. 5,874, 590

Kit Components Only

Product No.

  • Diphenyleneiodonium Chloride (DPI) 1 mM 200 μL

  • Arginine Substrate Solution for NOS Detection, Fluorimetric 2 mL

Kit Components Also Available Separately

Product No.

  • D225Diaminofluorescein-2 diacetate (DAF2-DA) 1 mL/vialSDS

  • N9910β-Nicotinamide adenine dinucleotide 2′-phosphate reduced tetrasodium salt, vial of 0.30-0.36 mg 1 vialSDS

Storage Class

10 - Combustible liquids




Not applicable


Not applicable

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