Merck, 803677-50MG, EMCH (N-(ε-maleimidocaproic acid) hydrazide, trifluoroacetic acid salt)

General description
3,3′-N-[ε-Maleimidocaproic acid] hydrazide, trifluoroacetic acid salt (EMCH) is a water-soluble, heterobifunctional, membrane permeable crosslinker. It contains a sulfhydryl reactive maleimide group and carbonyl reactive hydrazide group at each end of a 6-carbon spacer arm. Maleimides react with sulfhydryls at pH 6.5-7.5 to form stable thiol ether bonds, along with release of the maleimide leaving group. Proteins with cysteine residues not involved in disulfide bond formation are targets for maleimide reactive groups. Carbonyl groups, whilst not found naturally on proteins can be formed by ring sugar reduction to form aldehydes which react with hydrazides at pH5.5-7.5.
Features and Benefits

• Reactive groups: maleimide and hydrazide
• Reactive towards: sulfhydryl groups and carbonyl (aldehyde) groups
• Mid-length (11.8Å), sulfhydryl-to-aldehyde crosslinker with simple spacer arm (noncleavable)
• Maleimide group reacts with sulfhydryl groups to form stable thioether linkages
• Hydrazide group conjugates to oxidized sugars of glycoproteins and carbohydrates
• Use sodium meta-periodate to oxidize glycosylation (e.g., sialic acid) to reactive aldehyde groups
• Use with EDC to conjugate primary amine of hydrazide group to carboxyl groups

Disclaimer
This product is sensitive to moisture. The vial is packaged in a resealable bag with a desiccant to reduce exposure to moisture. After cold storage, equilibrate the vial to room temperature before opening to reduce condensation inside the vial. Make fresh solutions. Storage of stock solutions is not recommended. After use, return the vial to the resealable bag. Close the bag and store the product at the recommended temperature.