Methemoglobin formation in hemoglobin vesicles and reduction by encapsukated thiols

Shinji Takeoka, Hiromi Sakai, Takehiro Kose, Yuichi Mano, Yuriko Seino, Hiroyuki Nishide, Eishun Tsuchida

研究成果: Article

36 引用 (Scopus)

抄録

The hemoglobin vesicle (HbV) is a red cell substitute encapsulating purified concentrated Hb in a phospholipid vesicle. In order to suppress metHb formation or autoxidation, for the long-term maintenance of the oxygen transporting capability, a series of thiols (cysteine, Cys; glutathione, GSH; homocysteine, Hcy; and acetylcysteine, Acy) were studied as reductants of metHb. Hcy and GSH showed a good suppressive effect on metHb formation, while Cys adversely accelerates the metHb formation at a rate twice that of the Hb solution without any reductants and Acy showed no change. The significant suppression by the coaddition of superoxide dismutase (SOD) and catalase to Cys indicated that Cys was easily oxidized by oxygen and simultaneously generates a large amount of active oxygens. The effective suppression of metHb formation by SOD and catalase was not observed for HbV containing no reductants, indicating that the generation of active oxygens from Hb itself is not significant. The coencapsulation of Hcy with Hb resulted in a low rate of metHb formation in HbV (initial rate, 1%/h) in vitro at oxygen partial pressure (P(O2)) of 142 Torr. The rate increased with decreasing P(O2), showed a maximum (2.2%/h) around P(O2) = 23 Torr, and then decreased to 0%/h at 0 Torr. From these results, it is suggested that the fast metHb formation rate in the blood circulation of Wistar rats injected with 20 vol % of the HbV solution would be mainly caused by the exposure of HbV to the low P(O2).

元の言語English
ページ(範囲)539-544
ページ数6
ジャーナルBioconjugate Chemistry
8
発行部数4
DOI
出版物ステータスPublished - 1997 7

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Methemoglobin
Hemoglobin
Sulfhydryl Compounds
Hemoglobins
Reducing Agents
Oxygen
Catalase
Superoxide Dismutase
Reactive Oxygen Species
Acetylcysteine
Blood Substitutes
Blood Circulation
Partial Pressure
Phospholipids
Hemodynamics
Homocysteine
Partial pressure
Glutathione
Cysteine
Wistar Rats

ASJC Scopus subject areas

  • Chemistry(all)
  • Organic Chemistry
  • Clinical Biochemistry
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry

これを引用

Methemoglobin formation in hemoglobin vesicles and reduction by encapsukated thiols. / Takeoka, Shinji; Sakai, Hiromi; Kose, Takehiro; Mano, Yuichi; Seino, Yuriko; Nishide, Hiroyuki; Tsuchida, Eishun.

:: Bioconjugate Chemistry, 巻 8, 番号 4, 07.1997, p. 539-544.

研究成果: Article

Takeoka, Shinji ; Sakai, Hiromi ; Kose, Takehiro ; Mano, Yuichi ; Seino, Yuriko ; Nishide, Hiroyuki ; Tsuchida, Eishun. / Methemoglobin formation in hemoglobin vesicles and reduction by encapsukated thiols. :: Bioconjugate Chemistry. 1997 ; 巻 8, 番号 4. pp. 539-544.
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AU - Takeoka, Shinji

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AU - Kose, Takehiro

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AU - Nishide, Hiroyuki

AU - Tsuchida, Eishun

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