Methoxy poly(ethylene glycol)-Iodolacetyl (MPEG-IA) is one type of linear monofunctional PEG acid reagents. PEG-IA can be used to react with thiol groups.
Haloacetyl reaction chemistry: The most commonly used haloacetyl crosslinkers contain an iodoacetyl or a bromoacetyl group. Haloacetyls react with sulfhydryl groups at physiologic pH. The reaction of the iodoacetyl group proceeds by nucleophilic substitution of iodine with a sulfur atom from a sulfhydryl group, resulting in a stable thioether linkage.