A water-soluble amine-to-sulfhydryl crosslinker with a medium-length cyclohexane spacer arm.
AAT Bioquest Sulfo-SMCC is a popular, water-soluble, amine-to-sulfhydryl crosslinker that contains NHS-ester and maleimide reactive groups at opposite ends of a medium-length cyclohexane spacer arm (8.3 Å).
Sulfosuccinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (Sulfo-SMCC) is a water-soluble, non-cleavable and membrane impermeable 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 Sulfo-SMCC and SMCC are unusually stable up to pH 7.5 because of the cyclohexane bridge in the spacer arm. Because it contains the hydrophilic sulfonyl moiety, Sulfo-SMCC is soluble up to ~10 mM in water and many commonly used buffers, thus avoiding the use of organic solvents which may perturb protein structure.
Sulfo-SMCC is often used for the preparation of antibody-enzyme and hapten-carrier conjugates. In this type of conjugation, the NHS ester is reacted first with the antibody, excess crosslinking reagent removed and then the sulfhydryl-containing enzyme molecule is added. This two-step reaction scheme results in formation of specific antibody-enzyme conjugates.
Sulfo-SMCC is the reagent of choice for creating stable maleimide-activated carrier proteins that will spontaneously react with sulfhydryls. In this application, the NHS ester of Sulfo-SMCC is reacted with lysine residues on the carrier protein, converting them to reactive maleimides. These relatively stable maleimide-activated intermediates may be lyophilized and stored for later conjugation to a hapten.
|Properties of Sulfo-SMCC|
|Spacer arm length||8.3 Å (9 atom)|
|Storage conditions||-20°C, protect from moisture, use only fresh solutions|
|Purity||>90 % (determined by HPLC)|
|e. g. purity of current lot (as at 2011-06-20): 96%|
|Reactive groups:||NHS ester, reacts with primary amines at pH 7.0-9.0|
|Maleimide, reacts with sulfhydryls at pH 6.5-7.5|