Iodoacetamide

Iodoacetamide is a thiol reagent; alkylating reagent for cysteine and histidine residues in proteins. In the alkylation reaction, it reacts with histidine (such as in RNase), methionine and sulfhydryl groups of many proteins. Iodoacetamide can react with low molecular weight thiol compounds such as mercaptoethanol and glutathione. The reaction with glutathione is utilized in a titration method for the determination of sulfhydryl groups in different compounds. The alkylation reaction forms stable protein derivatives which will remain intact during further study of the protein.

Iodoacetamide is useful in peptide sequencing and as an irreversible enzyme inhibitor. Some enzymes iodoacetamide will inhibit include (but is not limited to): Alcohol dehydrogenase, Alkaline phosphatase (calf intestinal), beta-Amylase, Cathepsin B, Galactose oxidase, Heme oxygenase, L-Lysine decarboxylase. It will irreversibly inhibit the dephosphorylation of both epidermal growth factor receptor and platelet-derived growth factor receptor by alkylation at the active center of one or several protein tyrosine phosphatases in cell lines. Iodoacetamide will also irreversibly inhibit many cysteine proteases. Alkylating reagent for cysteine residues in peptide sequencing. By virtue of reaction with cysteine, it is an irreversible inhibitor of enzymes with cysteine at the active site. It reacts much more slowly with histidine residues, but that activity is responsible for inhibition of ribonuclease.