Characterization of insulin macroinitiator and insulin-trehalose glycopolymer conjugate. (A) Analytical HPLC and (B) MALDI MS after purification of the insulin macroinitiator, (C) Coomassie stained SDS PAGE (Lane 1: Ladder, Lane 2: Insulin, Lane 3: Purified insulin macroinitiator, Lane 4: Trehalose glycopolymer, Lane 5: Crude insulin-trehalose glycopolymer conjugate, Lane 6: Purified insulin-trehalose glycopolymer conjugate), (D) native PAGE with Western blot analysis (Lane 1: Insulin, Lane 2: Purified insulin macroinitiator, Lane 3: Trehalose glycopolymer, Lane 4: Crude insulin-trehalose glycopolymer conjugate, Lane 5: Purified insulin-trehalose glycopolymer conjugate Lane 6: Insulin-trehalose glycopolymer conjugate after digestion with Proteinase K), and (E) SEC trace of trehalose glycopolymer after digestion of insulin with Proteinase K.