Product Description

CellMosaic’s maleimide assay kit is designed to assay the maleimide functional group content of a modified biopolymer, such as an antibody, protein, peptide, or oligo. CellMosaic routinely uses this kit for its internal bioconjugation-related research.

The assay is based on Ellman’s assay of cysteine using 5’5’-dithio-bis-(2-nitrobenzoic acid) (DTNB) (Ellman, G.L. 1959, Tissue sulfhydryl groups. Arch Biochem Biophys. 82, 70–77). First, a known amount of excess cysteine is reacted with the maleimide groups of the biopolymer, and then the unreacted cysteine is reacted with DTNB to generate 2-nitro-5-thiobenzoic acid (TNB). TNB is orange in color and has an extinction coefficient of 14,150 M-1cm-1 at 412 nm (Riddles, P.W. Blakeley, R. L., and Zerner, B. 1983, Reassessment of Ellman’s reagent. Methods Enzymol. 91, 49-60). The difference between the initial amount of cysteine and the amount of unreacted cysteine corresponds to the maleimide functional groups of the biopolymer.

Four micro-centrifuge tubes per package. Each package is sufficient for 10 assays (100 μL per assay volume).

Application of the product:

• Assay the maleimide functional groups

Key Features of the product:

• Less than 1 h of preparation and assay time. Fast and easy to use.