MPS-Acid, product number 10323, is 3-maleimidopropanoic acid, a thiol-reactive crosslinker for linking sulfhydryl groups with free amines. Although it is not a dPEG® product, MPS-Acid is a building block for Quanta BioDesign’s complete line of Maleimide-dPEG®x products. 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. To learn more about maleimide reaction chemistry, go to our Maleimide Reaction Chemistry page.
This product can be functionalized with an active ester such as N-hydroxysuccinimide (NHS); 2,3,5,6-tetrafluorophenol (TFP); or 2,3,4,5,6-pentafluorophenol (PFP) in order to react with free amines. Alternatively, the acid moiety can be coupled directly to free amines using a water-soluble carbodiimide such as 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC).
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.
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). Click here now for a review of Greg’s book and a link to purchase it.
Hermanson, G. T. Chapter 18, PEGylation and Synthetic Polymer Modification. Bioconjugate Techniques, 3rd edition. Academic Press: New York, 2013, pages 787 – 838.