A label for sulfhydryl-containing proteins
Technical Support & Resources

Information provided in the product description is from published literature. Due to the nature of scientific experimentation, your results (e.g., selectivity and effective concentrations) or specific application for this product may differ. If you have questions about how this product fits your application, please contact our technical support staff.

Visit our FAQ

Contact Us

Toll Free Phone (USA and Canada Only): (888) 526-5351
Direct Phone: (734) 975-3888

Request Technical Support

Technical Support Request

To streamline the process attach the appropriate questionnaire to your inquiry.

Download IHC QuestionnaireDownload WB Questionnaire

View Our Privacy Statement for details on how we use and protect your data. In addition, this site is protected by hCaptcha and its Privacy Policy and Terms of Service apply.

Fluorescein-5-maleimide

Item No. 16383

Product Insert (PDF)Safety Data Sheet (SDS) (PDF)
Technical Information
Formal Name
1-(3',6'-dihydroxy-3-oxospiro[isobenzofuran-1(3H),9'-[9H]xanthen]-5-yl)-1H-pyrrole-2,5-dione
CAS Number
75350-46-8
Synonyms
  • 5-Maleimido-fluorescein
  • 5-MF
Molecular Formula
C24H13NO7
Formula Weight
427.4
Purity
≥90%
Emission
519 nm
Excitation
494 nm
Formulation (Request formulation change)
A solid
Solubility(Learn about Variance in Solubility)
DMF: 30 mg/mlDMSO: 20 mg/mlEthanol: 2 mg/ml
λmax
225, 278 nm
SMILES
OC1=CC2=C(C=C1)C3(C(C=CC(N4C(C=CC4=O)=O)=C5)=C5C(O3)=O)C6=CC=C(O)C=C6O2
InChi Code
InChI=1S/C24H13NO7/c26-13-2-5-17-19(10-13)31-20-11-14(27)3-6-18(20)24(17)16-4-1-12(9-15(16)23(30)32-24)25-21(28)7-8-22(25)29/h1-11,26-27H
InChi Key
AYDAHOIUHVUJHQ-UHFFFAOYSA-N
Shipping & Storage Information
Storage
-20°C
Shipping
Wet ice in continental US; may vary elsewhere
Recommended Products

Certificates of Analysis & Batch Specific Data

Provide batch numbers separated by commas to download or request available product inserts, QC sheets, certificates of analysis, data packs, and GC-MS data.

Download most recent Certificate of Analysis for this product

    5 mg

    $49

    Add

    10 mg

    $93

    Add

    25 mg

    $171

    Add

    50 mg

    $242

    Add
    Product Description

    Fluorescein-5-maleimide is an activated fluorescent molecule (excitation: 494 nm, emission: 519 nm) that is used to easily conjugate fluorescein to proteins.1,2,3 The maleimide group reacts optimally with sulfhydryl groups on cysteine side chains at pH 7, forming a stable thioether bond.4 The compound can be used to label proteins for the detection of conformational changes, assembly of multisubunit complexes, and ligand-binding processes.5

    WARNING This product is not for human or veterinary use.

    References & Product Citations
    Product Description References

    1. Curtis, S.K., and Cowden, R.R. Demonstration of sulfhydryl and disulfide groups by a fluorescent maleimide procedure. Histochemistry 68(1), 23-28 (1980).

    2. Elliott, J.T., Tona, A., and Plant, A.L. Comparison of reagents for shape analysis of fixed cells by automated fluorescence microscopy. Cytometry 52(2), 90-100 (2003).

    3. Lepedda, A.j., Zinellu, A., Nieddu, G., et al. Protein sulfhydryl group oxidation and mixed-disulfide modifications in stable and unstable human carotid plaques. Oxid. Med. Cell. Longev. 403973 (2013).

    4. Bigelow, D.J., and Inesi, G. Frequency-domain fluorescence spectroscopy resolves the location of maleimide-directed spectroscopic probes within the tertiary structure of the Ca-ATPase of sarcoplasmic reticulum. Biochemistry 30(8), 2113-2125 (1991).

    5. Taraska, J.W., and Zagotta, W.N. Fluorescence applications in molecular neurobiology. Neuron 66(2), 170-189 (2010).