Biomaterial Database

Redox reaction of poly(ethylene oxide)-modified hemoglobin in poly(ethylene oxide) oligomers at 120 degrees C. 1994

H Ohno, and N Yamaguchi

Department of Biotechnology, Tokyo University of Agriculture & Technology, Japan.

Human hemoglobin, modified with poly(ethylene oxide) with average molecular weight of 3500 (PEO-Hb) was dissolved in PEO200 (molecular weight of 200) containing 0.5 M KCl. A quasi-reversible redox reaction of the PEO-Hb was found in PEO oligomers by alternatingly changing the potential polarity (+/- 1.2 V vs Ag). The PEO-Hb showed redox reactions in PEO200 even at 120 degrees C. PEO modification was concluded to give the thermal stability in some extent. In phosphate buffer at 70 degrees C, the electrochemical redox reaction of native Hb was not observed spectroscopically, but that of PEO-Hb was detected. The most effective factor was, however, concluded to be the use of PEO oligomers as a solvent. The molecular motion of PEO oligomers should be milder than that of water at higher temperature. This lower molecular motion was suggested to keep the redox activity of PEO-Hb in the PEO oligomer at 120 degrees C. However, the PEO-Hb in PEO200 was stable in the oxidized form at 30 degrees C; it was reduced without giving potential at 120 degrees C. Cyclic voltammetry revealed that this autoreduction was attributed to the shift of redox potential with elevating temperature.

UI	MeSH Term	Description	Entries
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D011092	Polyethylene Glycols	Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.	Macrogols,Polyoxyethylenes,Carbowax,Macrogol,Polyethylene Glycol,Polyethylene Oxide,Polyethyleneoxide,Polyglycol,Glycol, Polyethylene,Glycols, Polyethylene,Oxide, Polyethylene,Oxides, Polyethylene,Polyethylene Oxides,Polyethyleneoxides,Polyglycols,Polyoxyethylene
D004563	Electrochemistry	The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.	Electrochemistries
D006418	Heme	The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.	Ferroprotoporphyrin,Protoheme,Haem,Heme b,Protoheme IX
D006454	Hemoglobins	The oxygen-carrying proteins of ERYTHROCYTES. They are found in all vertebrates and some invertebrates. The number of globin subunits in the hemoglobin quaternary structure differs between species. Structures range from monomeric to a variety of multimeric arrangements.	Eryhem,Ferrous Hemoglobin,Hemoglobin,Hemoglobin, Ferrous
D013056	Spectrophotometry, Ultraviolet	Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Ultraviolet Spectrophotometry
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures