Resins suitable for the Boc-SPPS of “peptide acids” (i.e. C-terminal carboxyl group):

Merrifield resin (chloromethyl resin) and hydroxymethyl resin, PAM (phenylacetamidomethyl) resin (only available in preloaded form) As esterification of the C-terminal Boc-amino acid can be accompanied by concomitant racemization, we recommend using preloaded resins. They are produced under conditions optimized for minimal racemization and tested for optical purity.

Resins suitable for the Boc-SPPS of peptide amides:

MBHA resin (4-methyl-benzhydrylamine resin), BHA resin (benzhydrylamine resin)

Both resins are offered as hydrochlorides, the amino group has to be liberated before coupling the C-terminal Boc-amino acid. As the loading step can be easily included in standard Boc-SPPS protocols, we do not offer preloaded amide resins.