Effects of Polyols, Saccharides, and Glycoproteins on Thermoprecipitation of Phenylboronate-Containing Copolymers

• Published in: Biomacromolecules Vol. 7; no. 4; pp. 1017 - 1024
• Main Authors: Ivanov, Alexander E, Shiomori, Koichiro, Kawano, Yoshinobu, Galaev, Igor Yu, Mattiasson, Bo
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.04.2006
• Subjects: Acrylamides - chemistry; Applied sciences; Boronic Acids - chemistry; Chemical Precipitation; Engineering and Technology; Exact sciences and technology; Glycoproteins - chemistry; Industrial Biotechnology; Industriell bioteknik; Molecular Structure; Oligosaccharides - chemistry; Organic polymers; Physicochemistry of polymers; Polymers - chemical synthesis; Polymers - chemistry; Polymers with particular properties; Preparation, kinetics, thermodynamics, mechanism and catalysts; Teknik; Temperature; Aldose; Chemical precipitation; Glycoprotein; Acrylamide derivative copolymer; Experimental study; Solute effect; Lateral group; Boron copolymer; Intermolecular interaction; Cloud point; Aminoglycoside; Preparation; Aqueous solution; Radical copolymerization; Boronic acids
• ISSN: 1525-7797; 1526-4602; 1526-4602
• DOI: 10.1021/bm050208i

The copolymer of 3-(acrylamido)phenylboronic acid and N-isopropylacrylamide (82:18, M n = 47000 g/mol) was prepared by free radical polymerization. The copolymer showed typical thermoprecipitation behavior in aqueous solutions; its phase transition temperature (T P) was 26.5 ± 0.2 °C in 0.1 M glycine−NaOH buffer containing 0.1 M NaCl, pH 9.2. Due to specific complex formation of the pendant boronates with sugars, T P was strongly affected by the type of sugar and its concentration at pH 9.2. Fructose, lactulose, and glucose caused the largest increase in T P (up to 4 °C) at 0.56 mM concentration, attributed to the high binding affinity of the sugars to borate and phenylboronate. Among the sugars typical of nonreducing ends of oligosaccharides, N-acetylneuraminic acid had the strongest effect on T P (ca. 2 °C at 0.56 mM concentration and pH 9.2), while the effects of other sugars are well expressed at the higher concentrations (16 and 80 mM) and decreased in the order xylose ≈ galactose ≥ N-acetyllactosamine ≥ mannose ≈ fucose ≫ N-acetylglucosamine. The effect exerted on the phase transition by glycoproteins was the strongest with mucin from porcine stomach and decreased in the series mucin > horseradish peroxidase > human γ-globulin at pH 9.2. As a first approximation, the weight percentage and/or the number of oligosaccharides in glycoproteins determined the character of their interaction with the pendant phenylboronates and, therefore, the effect on the copolymer phase transition.