Sepharose is a tradename for a crosslinked, beaded-form of agarose, a polysaccharide polymer material extracted from seaweed.
A common application for the material is in chromatographic separations of biomolecules.
[1] Iodoacetyl functional groups can be added to selectively bind cysteine side chains and this method is often used to immobilize peptides.
Sepharose/agarose, combined with some form of activation chemistry, is also used to immobilize enzymes, antibodies and other proteins and peptides through covalent attachment to the resin.
Common activation chemistries include cyanogen bromide (CNBr) activation and reductive amination of aldehydes to attach proteins to the agarose resin through lysine side chains.