MPS (NHS-3-maleimidopropionate)

MPS (NHS-3-maleimidopropionate), product number 10217, is the N-hydroxysuccinimidyl (NHS) ester of 3-(maleimido)propanoic acid. This product is not a dPEG® reagent. It is one of the building blocks for Quanta BioDesign's line of maleimide-functionalized dPEG® reagents. As a crosslinker, the distance is 6 atoms (6.0 Å) from the reactive site of the maleimide to the carbonyl carbon of the propanoic acid.


The maleimido group reacts with sulfhydryl groups to form thiol ether bonds. In the range of pH 6.5 – 7.5, the thiol-maleimide reaction is chemoselective. Above pH 7.5, the maleimide group can also react with free amine groups. Consequently, high pH buffers should be avoided when using this product.

NHS esters are widely popular for reactions of carboxylic acids with primary or secondary amines to form stable amide bonds. Although the NHS ester hydrolyzes rather easily in water or aqueous buffer, this product can be dissolved in a water-miscible solvent such as N,N'-dimethylacetamide (DMAC) that has been dried over 3 Å molecular sieves. The solution of MPS is then added to the water or aqueous buffer to start the reaction.

If you need bulk product in a larger package size than our standard sizes, please contact us for a quote. Our commercial capabilities permit us to manufacture this product at any scale that you need.

Application References:

Hermanson, G. T. Chapter 3, The Reactions of Bioconjugation. Bioconjugate Techniques, 3rd edition. Academic Press: New York, 2013, pages 229 – 258, particularly pages 233-234 (NHS ester), page 238 (fluorophenyl esters), and page 241 (maleimide reactive group).
Hermanson, G. T. Chapter 18, PEGylation and Synthetic Polymer Modification. Bioconjugate Techniques, 3rd edition. Academic Press: New York, 2013, pages 787 – 838.

Please contact us at for specific academic pricing.