Name: Amplite® Colorimetric Maleimide Quantitation Kit
Brand: AAT Bioquest
SKU: 5525
Price: 237 USD
Availability: InStock

Amplite® Colorimetric Maleimide Quantitation Kit

Amplite® Colorimetric Maleimide Quantitation Kit is a colorimetric assay kit for quantifying maleimide groups through a thiol-consumption assay with a spectrophotometric readout.

Colorimetric detection: Quantifies residual thiol with 4,4'-DTDP after maleimide reacts with excess thiol.
Signal advantage: Uses 4,4'-DTDP with a molar extinction coefficient of 19,800 M-1cm-1 for improved sensitivity over direct maleimide absorbance.
Maleimide-specific chemistry: Calculates maleimide from the difference between initial and unreacted thiol.
Microplate compatible: Read absorbance at 324 nm using a clear-bottom plate.
Applications: Suitable for quantifying maleimide groups in conjugation and bioconjugation workflows.

Chemical structure for Amplite® Colorimetric Maleimide Quantitation Kit.

Protocol

SDS

COA

Catalog	Size	Price	Quantity
5525	100 tests	Price

Overview

Maleimides can be directly assayed spectrophotometrically at 302 nm. However, the small extinction coefficient of 620 M-1cm-1 renders this assay insensitive, and the assay is further complicated by the protein absorbance at the same wavelength. This colorimetric maleimide assay kit quantifies maleimide groups by first reacting a sample with a known amount of thiol present in excess and then assaying the remaining unreacted thiol using 4,4'-DTDP with a molar extinction coefficient of 19,800 M -1cm-1. The amount of maleimide is calculated as the difference between the initial amount of thiol and the amount of unreacted thiol after the complete reaction of all maleimide groups. This spectrophotometric assay for the determination of maleimide groups is a reverse GSH assay. It takes advantage of the high reactivity of thiols of GSH with the maleimide moiety. Maleimide of the sample is allowed to form a stable thiosuccinimidyl linkage with GSH. After the reaction of the sample is complete, the excess GSH, i.e., the remaining thiols of GSH in the reaction mixture, is estimated by using 4,4'-DTDP. The amount of GSH reacted with the sample is titrated to determine the extent of maleimide. For more sensitive maleimide quantitation, we recommend that you use our fluorimetric kit # 5523 that has higher sensitivity.

Citations

View all 9 citations: Citation Explorer

Polysaccharide-conjugate vaccines for Burkholderia pseudomallei based on the O-antigens of serotypes A and B.

Authors:

Yan, Jingmin and Huang, Jinzhu and Lu, Xiaoxue and He, Xiaoyi and Rao, Chenglong and Nan, Dongqi and Lu, Haiyang and Guo, Linming and Li, Qian and Wang, Shiwei and others,

Journal:

Carbohydrate Polymer Technologies and Applications (2025): 100859

Perlecan-targeted nanoparticles for drug delivery to triple-negative breast cancer

Authors:

Khanna, Vidhi and Kalscheuer, Stephen and Kirtane, Ameya and Zhang, Wenqui and Panyam, Jayanth

Journal:

Future Drug Discovery (2019)

Conjugation with eight-arm PEG markedly improves the in vitro activity and prolongs the blood circulation of staphylokinase

Authors:

Qi, Fangbing and Hu, Chunyang and Yu, Weili and Hu, Tao

Journal:

Bioconjugate chemistry (2018)

Conjugation with an inulin-chitosan adjuvant markedly improves the immunogenicity of Mycobacterium tuberculosis CFP10-TB10. 4 fusion protein

Authors:

Yu, Weili and Hu, Tao

Journal:

Molecular Pharmaceutics (2016)

Successful acquisition of a neutralizing monoclonal antibody against a novel neutrophil-activating peptide, mitocryptide-1

Authors:

Hattori, Tatsuya and Nakashima, Kenta and Marutani, Takayuki and Kiso, Yoshiaki and Nishi, Yoshisuke and Mukai, Hidehito

Journal:

Biochemical and biophysical research communications (2015): 54--59

References

View all 38 references: Citation Explorer

Quantitation of microparticles released from coated-platelets

Authors:

Dale GL, Remenyi G, Friese P.

Journal:

J Thromb Haemost (2005): 2081

Determination of WR-1065 in human blood by high-performance liquid chromatography following fluorescent derivatization by a maleimide reagent ThioGlo3

Authors:

Chen J, Lu Z, Lawrence TS, Smith DE.

Journal:

J Chromatogr B Analyt Technol Biomed Life Sci (2005): 161

A new maleimide-bound acid-cleavable solid-support reagent for profiling phosphorylation

Authors:

Chowdhury SM, Munske GR, Siems WF, Bruce JE.

Journal:

Rapid Commun Mass Spectrom (2005): 899

Characterization of site-specific ScFv PEGylation for tumor-targeting pharmaceuticals

Authors:

Natarajan A, Xiong CY, Albrecht H, DeNardo GL, DeNardo SJ.

Journal:

Bioconjug Chem (2005): 113

Reactions of cysteines substituted in the amphipathic N-terminal tail of a bacterial potassium channel with hydrophilic and hydrophobic maleimides

Authors:

Li J, Xu Q, Cortes DM, Perozo E, Laskey A, Karlin A.

Journal:

Proc Natl Acad Sci U S A (2002): 11605

Usage and storage

Intended use

Research Use Only (RUO)

Instrument settings

Absorbance microplate reader
Absorbance	324 nm
Recommended plate	Clear bottom

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Page updated on October 8, 2026

Component A: MEA	1 vial
Component B: 4,4'-DTDP	1 vial
Component C: Assay Buffer	1 bottle (50 mL)
Component D: DMSO	1 vial (1 mL)