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Titolo:
Laser photolysis studies of oxy- and carbonylhemoglobin in red blood cells. Effects of cell membrane on reversible binding of O-2 and CO
Autore:
Hoshino, M; Sonoki, H; Suzuki, H; Adachi, H; Miyazaki, Y; Yamanaka, K;
Indirizzi:
Inst Phys & Chem Res, Wako, Saitama 3510198, Japan Inst Phys & Chem Res Wako Saitama Japan 3510198 o, Saitama 3510198, Japan Tokyo Inst Technol, Interdisciplinary Grad Sch Sci & Engn, Midori Ku, Kanagawa 2268502, Japan Tokyo Inst Technol Kanagawa Japan 2268502 ri Ku, Kanagawa 2268502, Japan Toyo Univ, Fac Engn, Dept Chem, Kawagoe, Saitama 3508585, Japan Toyo UnivKawagoe Saitama Japan 3508585 , Kawagoe, Saitama 3508585, Japan Nihon Univ, Coll Pharm, Dept Biochem Toxicol, Funabashi, Chiba 2748555, Japan Nihon Univ Funabashi Chiba Japan 2748555 Funabashi, Chiba 2748555, Japan
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 44, volume: 105, anno: 2001,
pagine: 10976 - 10982
SICI:
1520-6106(20011108)105:44<10976:LPSOOA>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
QUATERNARY CONFORMATIONAL-CHANGES; HUMAN-HEMOGLOBIN; LIGAND-BINDING; HUMAN OXYHEMOGLOBIN; NITRIC-OXIDE; CARBONMONOXY-HEMOGLOBIN; GEMINATE RECOMBINATION; SUBUNIT ASSOCIATION; TERTIARY-STRUCTURE; BETA-SUBUNIT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
59
Recensione:
Indirizzi per estratti:
Indirizzo: Hoshino, M Inst Phys & Chem Res, Wako, Saitama 3510198, Japan Inst Phys & Chem Res Wako Saitama Japan 3510198 3510198, Japan
Citazione:
M. Hoshino et al., "Laser photolysis studies of oxy- and carbonylhemoglobin in red blood cells. Effects of cell membrane on reversible binding of O-2 and CO", J PHYS CH B, 105(44), 2001, pp. 10976-10982

Abstract

Nanosecond laser photolysis studies of hemoglobin in red blood cells (RBCs) were performed to elucidate the effects of cell membrane on the oxygen uptake and release mechanism of RBCs. Oxy RBCs readily photodissociated O-2 by the 355-nm laser pulse to give deoxy RBCs, which return to oxy RBCs at I atm air within ca. 50 mus after the pulse. The decay of deoxy RBCs is expressed as a sum of the two exponential functions of time, indicating that theoxygen-rebinding reaction is composed of the two processes. The rate constants, k(f) and k(S), for the faster and slower processes of the oxygen rebinding, measured as a function of the oxygen concentration, revealed that (1) k(f) is independent of the oxygen concentration, [O-2], and (2) k(s) asymptotically increases with an increase in [O-2] to a limiting value. These kinetic results were markedly different from those obtained with the laser photolysis of oxyhemoglobin molecules in aqueous solutions. On the basis of the kinetic studies for oxygen rebinding, the cell membrane of RBCs is suggested to dominate the rates for oxygen uptake and release of hemoglobin in RBCs. For comparison with oxygen, the CO-binding reactions of deoxy RBCs and deoxyhemoglobin molecules in aqueous solutions were studied by laser flash photolysis. The decay profiles of deoxy RBCs produced by laser photolysisof carbonyl RBCs at various CO concentrations were identical with those ofdeoxyhemoglobin molecules in aqueous solutions. Thus, in contrast to O-2, CO molecules are supposed to freely diffuse in and out of RBCs through the cell membrane.

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Documento generato il 09/12/19 alle ore 03:54:17