POLYETHYLENE GLYCOL DERIVATIVES, PROCESS FOR PREPARING THE SAME AND MODIFIED PROTEIN

摘要

High purity polyethylene glycol derivatives of formula (I) are useful as protein modifiers of interferons, t-PA, EGF, various hormones, etc. The thus modified protein has minimized antigenicity, prolonged plasma half life, or improved transfer to tissue. A novel process for preparing high purity polyethylene glycol derivatives is also disclosed.