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 | Acesso ao texto completo restrito à biblioteca da Embrapa Instrumentação. Para informações adicionais entre em contato com cnpdia.biblioteca@embrapa.br. |
Registro Completo
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Biblioteca(s): |
Embrapa Instrumentação. |
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Data corrente: |
22/12/1999 |
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Data da última atualização: |
11/03/2010 |
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Autoria: |
MARTIN-NETO, L.; TABAK, M.; NASCIMENTO, O. R. |
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Afiliação: |
EMBRAPA-CNPDIA; USP-IFSC. |
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Título: |
Reversible structural changes in met Hb and met Mb induced by hydration degree: a quantitative ESR study. |
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Ano de publicação: |
1990 |
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Fonte/Imprenta: |
In: PAN AMERICAN ASSOCIATION OF BIOCHEMICAL SOCIETIES CONGRESS, 6., Feb. 1990, Sao Paulo, SP. Abstracts and program... Sao Paulo: Sociedade Brasileira de Bioquimica, 1990. |
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Páginas: |
p.144. |
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Série: |
(SBBq Annual Meeting, 19). |
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Idioma: |
Inglês |
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Notas: |
Ref.C-33. |
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Conteúdo: |
The dehydration of methemoglobins and metmyoglobins was monitored using ESR spectroscopy of the iron signal. The interconversion of the Fe(III) signal between the high spin form (g approximately 6) in solution and low spin forms (at g approximately 2) was quantitatively studied as a function of hydration. The dehydration process leads also to a loss of paramagnetism resulting in the appereance of around 40% Fe(II) in both proteins. In the remaining 60% of Fe(III) ESR is distributed as the residual high spin (g approximately 6 - 5% in MetHb and 35% in MetMb) and low spin forms (hemichromes H and P - 55% in MetHb and only hemichrome H - 25% in MetMb). All conformational changes were reversibly modulated by hydration degree and partially by lyophilization rate. The level of 0.40 grH2O/gr protein to Hb and 0,2 grH2O/gr protein to Mb was the critical hydration for the molecules return to aquo met form and correspond also to a minimal water content necessary to cover all the protein surface as obtained from other techniques. The fact of Hb to require twice more water molecules as compared with Mb to change his conformation could indicate important role in the maintenance of the subunit contacts and communication (cooperation?). |
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Palavras-Chave: |
Change; Degree; ESR; Hydration; Methemoglobin; Metmyoglobin; Structural; Study. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 02095naa a2200277 a 4500
001 1026605
005 2010-03-11
008 1990 bl --- 0-- u #d
100 1 $aMARTIN-NETO, L.
245 $aReversible structural changes in met Hb and met Mb induced by hydration degree$ba quantitative ESR study.
260 $c1990
300 $ap.144.
490 $a(SBBq Annual Meeting, 19).
500 $aRef.C-33.
520 $aThe dehydration of methemoglobins and metmyoglobins was monitored using ESR spectroscopy of the iron signal. The interconversion of the Fe(III) signal between the high spin form (g approximately 6) in solution and low spin forms (at g approximately 2) was quantitatively studied as a function of hydration. The dehydration process leads also to a loss of paramagnetism resulting in the appereance of around 40% Fe(II) in both proteins. In the remaining 60% of Fe(III) ESR is distributed as the residual high spin (g approximately 6 - 5% in MetHb and 35% in MetMb) and low spin forms (hemichromes H and P - 55% in MetHb and only hemichrome H - 25% in MetMb). All conformational changes were reversibly modulated by hydration degree and partially by lyophilization rate. The level of 0.40 grH2O/gr protein to Hb and 0,2 grH2O/gr protein to Mb was the critical hydration for the molecules return to aquo met form and correspond also to a minimal water content necessary to cover all the protein surface as obtained from other techniques. The fact of Hb to require twice more water molecules as compared with Mb to change his conformation could indicate important role in the maintenance of the subunit contacts and communication (cooperation?).
653 $aChange
653 $aDegree
653 $aESR
653 $aHydration
653 $aMethemoglobin
653 $aMetmyoglobin
653 $aStructural
653 $aStudy
700 1 $aTABAK, M.
700 1 $aNASCIMENTO, O. R.
773 $tIn: PAN AMERICAN ASSOCIATION OF BIOCHEMICAL SOCIETIES CONGRESS, 6., Feb. 1990, Sao Paulo, SP. Abstracts and program... Sao Paulo: Sociedade Brasileira de Bioquimica, 1990.
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