Nitric Oxide Synthase Detection System, Fluorimetric

sufficient for 200 reactions


Quality Level


sufficient for 200 reactions


not available in Japan

shipped in

wet ice

storage temp.


Gene Information

human ... NOS1(4842), NOS2(4843), NOS2B(201288), NOS2C(645740), NOS3(4846)

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/vial

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


NONH for all modes of transport

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Zeming Zhang et al.
Journal of cellular physiology, 234(11), 19715-19727 (2019-04-16)
Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling of the precapillary pulmonary arteries, with excessive proliferation of vascular cells. This study was performed to examine the effects of long noncoding RNA CPS1 intronic transcript 1 (CPS1-IT) on PAH...
D S Bredt et al.
Proceedings of the National Academy of Sciences of the United States of America, 86(22), 9030-9033 (1989-11-01)
Nitric oxide, which mediates influences of numerous neurotransmitters and modulators on vascular smooth muscle and leukocytes, can be formed in the brain from arginine by an enzymatic activity that stoichiometrically generates citrulline. We show that glutamate and related amino acids...
D J Stuehr
Annual review of pharmacology and toxicology, 37, 339-359 (1997-01-01)
Research on the biological roles of nitric oxide has revealed that it functions as an important signal and effector molecule in a variety of physiologic and pathologic settings. In animals, nitric oxide is synthesized enzymatically from L-arginine through the actions...
D A Geller et al.
Cancer metastasis reviews, 17(1), 7-23 (1998-04-17)
Nitric oxide (NO) is a potent biologic mediator with diverse physiologic and pathophysiologic roles. NO is produced from L-arginine by the family of nitric oxide synthase (NOS) enzymes, forming the free radical NO and citrulline as byproduct. Three distinct isoforms...
H Kojima et al.
Chemical & pharmaceutical bulletin, 46(2), 373-375 (1998-03-21)
Endogenous nitric oxide (NO) appears to modulate many physiological and pathophysiological processes. In order to obtain direct evidence for NO functions in vivo, we have developed 4,5-diaminofluorescein (DAF-2) as a novel fluorescent indicator for NO. Green-fluorescent triazolofluorescein formed by the...

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