根据以下实验结果推断一多肽链的氨基酸序列: (1)酸水解其氨基酸组成:Ala 2 ,Arg,Lys 2 ,Met,Phe,Ser 2 (2)羧肽酶A水解得:Ala (3)胰蛋白酶水解得四个肽段: (Ala,Arg)(Lys,Phe,Ser)(Lys) (Ala ,Met ,Ser) (4)溴化氰水解得两个肽段: (Ala,Arg,Lys 2 ,Met,Phe,Ser) (Ala ,Ser) (5)嗜热菌蛋白酶水解得两个肽段: (Ala,Arg,Ser) (Ala,Lys 2 ,Met,Phe,Ser)