title: Polyethylene glycol improves conjugation of bovine hemoglobin and human serum albumin in a controlled ratio.
abstract: Direct conjugation of bovine hemoglobin (Hb) and human serum albumin (HSA) with glutaraldehyde would result in a complex mixture of dimers Hb-Hb, Hb-HSA, HSA-HSA and other oligomers. To obtain a high yield of target Hb-HSA, modulation of the reaction environment was carried out. It was found that polyethylene glycol (PEG), a hydrophilic polymer, could improve the yield of Hb-HSA conjugate. The degree of improvement depended on the molecular weight and concentration of PEG. Under optimum condition of 9% (w/v) of PEG 4000, the reaction proceeded in a controlled mode with conversion yield of starting proteins to Hb-HSA increasing from 6% to 30%. The purity was about 88% of the total conjugates. Furthermore, the impurities were mainly tetrameric molecules of two Hb-HSA conjugates. The improvement could be attributed to the "micro-compartment" created by addition of polyethylene glycol, which brings HSA and Hb close together, thus increasing the chance of conjugation between the two molecules.
authors: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China.
authors: Chunyang
authors: C
authors: Zheng
authors: Jingxiu
authors: J
authors: Bi
authors: Guanghui
authors: G
authors: Ma
authors: Zhiguo
authors: Z
authors: Su
mesh_terms: D000818:Animals; D001802:Blood Substitutes / Q000138:chemical synthesis / Q000378:metabolism; D002417:Cattle; D005976:Glutaral / Q000494:pharmacology; D006454:Hemoglobins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008954:Models, Biological; D011092:Polyethylene Glycols / Q000494:pharmacology*; D011108:Polymers / Q000138:chemical synthesis* / Q000378:metabolism*; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism*; D023822:Tissue Engineering / Q000379:methods
chemical_list: D001802:Blood Substitutes; D006454:Hemoglobins; D011108:Polymers; D012709:Serum Albumin; D011092:Polyethylene Glycols; D005976:Glutaral