Used for long-acting of pegylation of biopharmaceuticals. Two different functional terminals on linear peg molecular, provide more options for protein drugs pegylation, improve the pegylation efficiency, also could improve the targeting effect of protein drugs. Aa-peg-sc [-acryloyl--succinimidyl poly(ethylene glycol)] Aa-peg-ma [-acryloyl--methacryloyl poly(ethylene glycol)] Aa-peg-sh [-acryloyl--mercapto poly(ethylene glycol)] Aa-peg-mal [-acryloyl--maleinidyl poly(ethylene glycol)] Aa-peg-nco [-acryloyl--isocyanato poly(ethylene glycol)] Aa-peg-oh [-acryloyl--hydroxyl poly(ethylene glycol)] Aa-peg-eo [-acryloyl--glycidyl poly(ethylene glycol)] Aa-peg-cho [-acryloyl--formyl poly(ethylene glycol)] Aa-peg-cooh [-acryloyl--carboxyl poly(ethylene glycol)] Aa-peg-n3 [-acryloyl--azido poly(ethylene glycol)] Aa-peg-nh2 [-acryloyl--amino poly(ethylene glycol)] Aa-peg-alkyne [-acryloyl--allyl poly(ethylene glycol)]