Iodoacetamide

Iodoacetamide is a chemical compound with the formula CH₃CONHCH₂I. It is used in biochemistry and molecular biology as an alkylating agent, modifying cysteine residues in proteins and enzymes, and as a specific inhibitor of glutathione reductase. Iodoacetamide reacts with the thiol groups of cysteine to form S-carboxyamidomethylcysteine, a modification that can be detected and analyzed by mass spectrometry or electrophoresis, making it a valuable tool for protein sequencing and proteomics studies.

Properties

Iodoacetamide is a white crystalline solid that is soluble in water and common organic solvents. It is sensitive to light and moisture, and it should be stored in a dark, dry place to prevent degradation. The compound's reactivity with thiol groups makes it a potent inhibitor of enzymes containing active site cysteine residues.

Applications in Biochemistry

In biochemistry, iodoacetamide is primarily used for the alkylation of cysteine residues in proteins. This modification prevents the formation of disulfide bonds, thereby stabilizing proteins in their reduced form during SDS-PAGE analysis. It is also used in the preparation of samples for mass spectrometry by preventing cysteine residues from forming disulfide-linked oligomers, which can complicate the analysis.

Another application of iodoacetamide is in the study of enzyme kinetics and mechanisms. By irreversibly inhibiting enzymes that rely on cysteine thiol groups for activity, researchers can investigate the role of these residues in enzyme function.

Safety and Handling

Iodoacetamide is toxic and should be handled with care in a well-ventilated area while wearing appropriate protective equipment. It is a skin and eye irritant, and exposure can cause serious health issues. Proper disposal procedures for hazardous chemicals should be followed.

See Also

• Alkylation
• Cysteine
• Protein sequencing
• Proteomics