A sterilized composition sterilized by radiation and containing a protein and an aliphatic polyester containing said protein. This sterilized composition retains the structure and function (activity) of the protein.本發明係提供一種包含蛋白質以及含有該蛋白質之脂肪族聚酯,經放射線滅菌之滅菌組成物。利用該滅菌組成物,可維持蛋白質的構造與功能(活性)。