Iodoacetamido-PEG-t-butyl ester is a compound used in pharmaceutical research and development as a tool for modifying proteins. It is a derivative of polyethylene glycol (PEG) that contains functional groups, such as the iodoacetamide group, which enables selective and irreversible modification of cysteine residues in proteins. The t-butyl ester group provides stability to the compound, allowing for prolonged storage and easy handling. Iodoacetamido-PEG-t-butyl ester is particularly useful in the development of protein therapeutics, where it can be used to conjugate PEG to proteins, improving their pharmacokinetic properties, such as stability and half-life in the bloodstream. The functional groups in Iodoacetamido-PEG-t-butyl ester make it a versatile tool for researchers in the pharmaceutical industry, allowing for the modification of proteins in a precise and controlled manner.