AAT Bioquest

Protonex™ Green 500WS

Emission Spectra of Protonex™ Green 500 at different pH.
Emission Spectra of Protonex™ Green 500 at different pH.
Emission Spectra of Protonex™ Green 500 at different pH.
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Physical properties
Molecular weight775.63
Spectral properties
Extinction coefficient (cm -1 M -1)4000
Excitation (nm)445
Emission (nm)503
Storage, safety and handling
Intended useResearch Use Only (RUO)
StorageFreeze (< -15 °C); Minimize light exposure


Molecular weight
Extinction coefficient (cm -1 M -1)
Excitation (nm)
Emission (nm)
Protonex™ Green dye demonstrated pH-dependent fluorescence. Unlike most of the existing fluorescent dyes that are more fluorescent at higher pH, acidic conditions enhance the fluorescence of Protonex™ Green dye. The fluorescence of Protonex™ Green dye significantly increases as pH decreases from neutral to the acidic. Protonex™ Green dye provides a powerful tool to monitor acidic cell compartments such as endosomes, lysosomes and other biological targets. Protonex™ Green 500 WS is not permeable to live cells, enabling the specific detection of extracellular acidic biological targets. Protonex™ Green has the spectral properties similar to those of FITC, making the common filter set of FITC readily available to the assays of Protonex™ Green.


Common stock solution preparation

Table 1. Volume of DMSO needed to reconstitute specific mass of Protonex™ Green 500WS to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

0.1 mg0.5 mg1 mg5 mg10 mg
1 mM128.927 µL644.637 µL1.289 mL6.446 mL12.893 mL
5 mM25.785 µL128.927 µL257.855 µL1.289 mL2.579 mL
10 mM12.893 µL64.464 µL128.927 µL644.637 µL1.289 mL

Molarity calculator

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Spectral properties

Extinction coefficient (cm -1 M -1)4000
Excitation (nm)445
Emission (nm)503

Product Family

NameExcitation (nm)Emission (nm)Extinction coefficient (cm -1 M -1)
Protonex™ Green 5004455034000



View all 20 citations: Citation Explorer
Starch-regulated copper-terephthalic acid as a pH/hydrogen peroxide simultaneous-responsive fluorescent probe for lysosome imaging
Authors: Chen, J., Si, Y., Liu, Y., Wang, S., Wang, S., Zhang, Y., Yang, B., Zhang, Z., Zhang, S.
Journal: Dalton Trans (2019): 13017-13025
A structure optimized fluorescent probe for highly sensitive monitoring drug induced lysosomal pH value changes
Authors: Gong, Y. J., Kong, Z. Z., Zhang, M. L., Lv, M. K., Zhang, G.
Journal: Talanta (2019): 1-8
An effective FRET-based two-photon ratiometric fluorescent probe with double well-resolved emission bands for lysosomal pH changes in living cells and zebrafish
Authors: Yuan, G., Ding, H., Zhou, L.
Journal: Spectrochim Acta A Mol Biomol Spectrosc (2019): 117397
A pH probe inhibits senescence in mesenchymal stem cells
Authors: Wang, L., Han, X., Qu, G., Su, L., Zhao, B., Miao, J.
Journal: Stem Cell Res Ther (2018): 343
Dual site-controlled two-photon fluorescent probe for the imaging of lysosomal pH in living cells
Authors: Wang, C., Dong, B., Kong, X., Zhang, N., Song, W., Lin, W.
Journal: Luminescence (2018): 1275-1280
Selective imaging of cancer cells with a pH-activatable lysosome-targeting fluorescent probe
Authors: Shi, R., Huang, L., Duan, X., Sun, G., Yin, G., Wang, R., Zhu, J. J.
Journal: Anal Chim Acta (2017): 66-73
A lysosome-locating and acidic pH-activatable fluorescent probe for visualizing endogenous H2O2 in lysosomes
Authors: Liu, J., Zhou, S., Ren, J., Wu, C., Zhao, Y.
Journal: Analyst (2017): 4522-4528
Two-photon imaging of formaldehyde in live cells and animals utilizing a lysosome-targetable and acidic pH-activatable fluorescent probe
Authors: Xie, X., Tang, F., Shangguan, X., Che, S., Niu, J., Xiao, Y., Wang, X., Tang, B.
Journal: Chem Commun (Camb) (2017): 6520-6523
A fluorescent pH probe for acidic organelles in living cells
Authors: Chen, J. W., Chen, C. M., Chang, C. C.
Journal: Org Biomol Chem (2017): 7936-7943
Near-Infrared Probe Based on Rhodamine Derivative for Highly Sensitive and Selective Lysosomal pH Tracking
Authors: Niu, G., Zhang, P., Liu, W., Wang, M., Zhang, H., Wu, J., Zhang, L., Wang, P.
Journal: Anal Chem (2017): 1922-1929