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Titolo:
Hemin (Fe3+)- and heme (Fe2+)-smectite conjugates as a model of hemoprotein based on spectrophotometry
Autore:
Itoh, T; Yamada, T; Kodera, Y; Matsushima, A; Hiroto, M; Sakurai, K; Nishimura, H; Inada, Y;
Indirizzi:
Toin Univ Yokohama, Dept Biomed Engn, Toin Human Sci & Technol Ctr, Aoba Ku, Yokohama, Kanagawa 2258502, Japan Toin Univ Yokohama Yokohama Kanagawa Japan 2258502 anagawa 2258502, Japan
Titolo Testata:
BIOCONJUGATE CHEMISTRY
fascicolo: 1, volume: 12, anno: 2001,
pagine: 3 - 6
SICI:
1043-1802(200101/02)12:1<3:H(AH(C>2.0.ZU;2-Y
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOTOSTABLE CHLOROPHYLL-A; SMECTITE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
15
Recensione:
Indirizzi per estratti:
Indirizzo: Inada, Y Toin Univ Yokohama, Dept Biomed Engn, Toin Human Sci & Technol Ctr, Aoba Ku, Kurogane Cho, Yokohama, Kanagawa 2258502, Japan Toin Univ Yokohama Kurogane Cho Yokohama Kanagawa Japan 2258502 n
Citazione:
T. Itoh et al., "Hemin (Fe3+)- and heme (Fe2+)-smectite conjugates as a model of hemoprotein based on spectrophotometry", BIOCONJ CHE, 12(1), 2001, pp. 3-6

Abstract

Hemin (Fe3+) was adsorbed onto synthetic smectite (clay mineral) in acetone to form a hemin-smectite conjugate. The hemin-smectite conjugate became soluble in water to form a transparent colloidal solution with a dark brown color. Its absorption spectrum in water showed a sharp Soret band at 398 nmwith the molar extinction coefficient as epsilon (398nm) = 11.6 x 10(4) M-1 Cm-1, which is in good agreement with epsilon (398nm) = (12.2 +/- 3) x 10(4) M-1 cm(-1) of monomeric hematin (1). Hamin (Fe3+)-smectite conjugate had a peroxidase-like activity in the presence of hydrogen peroxide (a hydrogen acceptor) and guaiacol (a hydrogen donor) in aqueous solution and its activity was higher than that of hematin. Hemin (Fe3+)-smectite conjugate in water was reduced by adding sodium dithionite to form a heme (Fe2+)-smectite conjugate which is also a transparent colloidal solution in water. Its absorption spectrum in aqueous solution was surprisingly in close agreement with that of oxyhemoglobin. Its peak positions of alpha, beta, and Soret bands were located in only a 9-3 nm shift to shorter wavelengths in comparisonwith those of oxyhemoglobin. Therefore, heme (Fe2+)-smectite conjugate wasbound to O-2 to form O-2-heme (Fe2+)-smectite conjugate. The addition of carbon monoxide, CO, to O-2-heme (Fe2+)-smectite conjugate caused the formation of CO-heme (Fe2+)-smectite conjugate with a similar absorption spectrumof carboxyhemoglobin (HbCO) accompanied by shifting 8-10 nm to shorter wavelength. Therefore, the transformation of O-2-heme (Fe2+)-smectite conjugate to CO-heme (Fe2+)-smectite conjugate was accompanied by shifting of 7, 4,and 3 nm to shorter wavelengths in the alpha, beta, and Soret bands respectively, which are similar to the spectral change from oxyhemoglobin to carboxyhemoglobin. Also the ratio (1:1.6) of the molar extinction coefficient of Soret band of O-2-heme (Fe2+)-smectite conjugate and CO-heme (Fe2+)-smectite conjugate was surprisingly agreement with ratio (1:1.5) of oxyhemoglobin and carboxyhemoglobin. The phenomenon shown above was unexpectedly found during the course of study of bioconjugate of a bioactive substance, hemin (Fe3+) or heme (Fe2+), and a clay mineral, smectite, in place of the protein of globin in hemoglobin.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/10/20 alle ore 00:28:22