Bis(sulfosuccinimidyl) Suberate

Bis(sulfosuccinimidyl) Suberate (BSSS) is a cross-linker molecule commonly used to prepare protein conjugates.  It is a water-soluble version of Disuccinimidyl Suberate (DSS).  It is hydrophilic because of the terminal sulfonyl groups on the molecule.  The benefit of this is that it can be used without organic solvents, which could denature or inhibit the proteins being used in solution.  BSSS is charged, making it impermeable to cell membranes.  This makes it ideal for reactions with proteins on the surface of cells.  It is also non-cleavable due to an 8-atom spacer in the molecule.  Thus, it forms robust covalent linkages to its target proteins.  It has two identical N-hydroxysulfosuccinimide (Sulfo-NHS) ester groups, which can readily react with primary amines.  The two ester groups also readily form cross-linkages between the conjugate molecules.

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