SMCC (Thermo Scientific™)

Thermo Scientific Pierce SMCC is a hetero-bifunctional crosslinker that contain N-hydroxysuccinimide (NHS) ester and maleimide groups that allow covalent conjugation of amine- and sulfhydryl-containing molecules. NHS esters react with primary amines at pH 7–9 to form amide bonds, while maleimides react with sulfhydryl groups at pH 6.5–7.5 to form stable thioether bonds. In aqueous solutions, NHS ester hydrolytic degradation is a competing reaction whose rate increases with pH. The maleimide group is more stable than the NHS-ester group, but will slowly hydrolyze and lose its reaction specificity for sulfhydryls at pH values > 7.5. For these reasons, conjugations with these crosslinkers are usually performed at pH 7.2–7.5, with the NHS ester (amine-targeted) reacted before or simultaneous with the maleimide (sulfhydryl-targeted) reaction.

The cyclohexane ring in the spacer arm of this reagent decreases the rate of hydrolysis of the maleimide group compared to similar reagents that do not contain this ring. This feature enables proteins that have been maleimide-activated with SMCC to be lyophilized and stored for later conjugation to a sulfhydryl-containing molecule. Many maleimide-activated protein products are produced in this manner.

Thermo Scientific No-Weigh products are specialty reagents provided in a pre-aliquoted format. The pre-weighed packaging prevents the loss of reagent reactivity and contamination over time by eliminating the repetitive opening and closing of the vial. The format enables use of a fresh vial of reagent each time, eliminating the hassle of weighing small amounts of reagents and reducing concerns over reagent stability.

Features of SMCC:

• Reactive groups: NHS ester and maleimide
• Reactive toward: amino and sulfhydryl groups
• Non-cleavable
• Water-insoluble (dissolve first in DMF or DMSO); compare to Sulfo-SMCC
• High purity, crystalline reagent can be used to create high-purity maleimide-activated derivatives
• Cyclohexane bridge confers added stability to the maleimide group making SMCC an ideal crosslinking agent for maleimide activation of proteins. Maleimide groups are stable for 64 hours in 0.1 M sodium phosphate buffer, pH 7 at 4°C.

Succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC) is a non-cleavable and membrane permeable crosslinker. It contains an amine-reactive N -hydroxysuccinimide (NHS ester) and a sulfhydryl-reactive maleimide group. NHS esters react with primary amines at pH 7-9 to form stable amide bonds. Maleimides react with sulfhydryl groups at pH 6.5-7.5 to form stable thioether bonds. The maleimide groups of SMCC and Sulfo-SMCC and are unusually stable up to pH 7.5 because of the cyclohexane bridge in the spacer arm.

Applications:
• Enzyme labelling of antibodies - both enzyme and antibody specificity can be preserved
• Create specific bioconjugates via one- or two-step crosslinking reactions
• Create sulfhydryl-reactive, maleimide-activated carrier proteins for coupling haptens

Specifications:
We manufacture SMCC to the highest specifications to produce the most specific bioconjugates and maleimide-activated proteins, ensure the integrity of your data and to provide you with the highest degree of crosslinking consistency. Each lot of SMCC is tested to meet the following minimum specifications.

• Identity: IR scan shows only peaks characteristic of the structure and functional groups of SMCC cross linker
• Purity: ≥ 92% by NMR

Product References:
Crosslinker Application Guide -- search for recent literature references for this product