Figure 1: Preparation of well-defined pOEGMA–ASNase conjugates.
From: Semi-permeable coatings fabricated from comb-polymers efficiently protect proteins in vivo
(a) Tetrameric ASNase possesses 92 amino groups (lysine residues and N-termini in red) that are evenly distributed on the solvent-exposed surface of the protein. Nineteen unique pOEGMA–ASNase conjugates were prepared by activation of a certain number (x) of these amino groups with 2-bromoisobutyryl bromide, followed in situ growth of different length (n) pOEGMA chains by atom transfer radical polymerization. (b) Analysis of the molecular weight of ASNase macro-initiators by matrix-assisted laser desorption/ionization–time of flight mass spectrometry to determine the average number of initiating groups per protein. (c) Representative size-exclusion chromatograms of pOEGMA–ASNase conjugates, mPEG–ASNase and native ASNase. All conjugates tested displayed monomodal molecular-weight distributions.
