Protonex™ Red 670 acid

Protonex™ Red 670 works by changing its fluorescence intensity depending on the pH of the environment. Protonex™ Red 670 is minimally fluorescent at a basic pH and maximally fluorescent at an acidic pH. When Protonex™ Red 670 is bound to a receptor or an antibody on the cell surface, it is essentially non-fluorescent because the extracellular pH is neutral. However, when the receptor or antibody is internalized into the cell in response to a stimulus, it enters the endosomal pathway, where the pH is acidic. This causes Protonex™ Red 670 to become highly fluorescent and emit red light when excited by a red laser such as a 632 nm He-Ne or 647 nm red laser. By measuring the fluorescence intensity of Protonex™ Red 670, one can monitor the activation and trafficking of receptors or antibodies in live cells. Protonex™ Red 670 is especially useful in studying the activation and trafficking of G protein-coupled receptors (GPCRs), one of the most popular therapeutic drug targets. Protonex™ Red 670 can be used to label any receptor or epitope tag antibody and monitor its movement from the cell surface into acidic endosomes upon agonist stimulation. Protonex™ Red 670 can also be used to measure high-potency agonist and antagonist responses of different GPCRs in live cells, such as the activation of TRHR-1 and beta-adrenoceptor, two GPCRs that are involved in hormone regulation and cardiovascular function.

Fluorescence response of Protonex™ Red 670 at different pH levels.

Datasheet

SDS

COA

Catalog	Size	Price	Quantity
21181	1 mg	Price

Calculators

Common stock solution preparation

Table 1. Volume of DMSO needed to reconstitute specific mass of Protonex™ Red 670 acid to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

	0.1 mg	0.5 mg	1 mg	5 mg	10 mg
1 mM	158.791 µL	793.953 µL	1.588 mL	7.94 mL	15.879 mL
5 mM	31.758 µL	158.791 µL	317.581 µL	1.588 mL	3.176 mL
10 mM	15.879 µL	79.395 µL	158.791 µL	793.953 µL	1.588 mL

Molarity calculator

Enter any two values (mass, volume, concentration) to calculate the third.

Mass (Calculate)		Molecular weight		Volume (Calculate)		Concentration (Calculate)		Moles
mg	÷	629.76 g/mol	=	mL	x	mM	=	mmol

References

View all 50 references: Citation Explorer

Mechanisms of 15-Epi-LXA4-Mediated HO-1 in Cytoprotection Following Inflammatory Injury.

Authors:

Wang, Meng and Tong, Kun and Chen, Zhe and Wen, Zhengde

Journal:

The Journal of surgical research (2023): 245-255

Generalization of the Ratiometric Method to Extend pH Range Measurements of the BCECF Probe.

Authors:

Tafech, Alaa and Beaujean, Céline and Usson, Yves and Stéphanou, Angélique

Journal:

Biomolecules (2023)

The phosphoinositide PI(3,5)P2 inhibits the activity of plant NHX proton/potassium antiporters: Advantages of a novel electrophysiological approach.

Authors:

Gradogna, Antonella and Pardo, José M and Carpaneto, Armando

Journal:

Biomolecular concepts (2022): 119-125

FLIM for Evaluation of Difference in Metabolic Status between Native and Differentiated from iPSCs Dermal Papilla Cells.

Authors:

Kashirina, Alena and Gavrina, Alena and Mozherov, Artem and Kozlov, Dmitriy and Kuznetsova, Daria and Vorotelyak, Ekaterina and Zagaynova, Elena and Kalabusheva, Ekaterina and Kashina, Aleksandra

Journal:

Cells (2022)

mOrange2, a Genetically Encoded, pH Sensitive Fluorescent Protein, is an Alternative to BCECF-AM to Measure Intracellular pH to Determine NHE3 and DRA Activity.

Authors:

Sarker, Rafiquel and Tse, Chung Ming and Lin, Ruxian and McNamara, George and Singh, Varsha and Donowitz, Mark

Journal:

Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology (2022): 39-49

Physical properties

Molecular weight	629.76
Solvent	DMSO

Spectral properties

Excitation (nm)	643
Emission (nm)	660

Usage and storage

Intended use	Research Use Only (RUO)
Storage	Freeze (< -15 °C); Minimize light exposure

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Page updated on August 29, 2026