Data/hora: 16/06/2024 23:03:44

Biblioteca(s): | Embrapa Instrumentação.
Data corrente: | 22/12/1999
Data da última atualização: | 11/03/2010
Autoria: | MARTIN-NETO, L.; TABAK, M.; NASCIMENTO, O. R.
Afiliação: | EMBRAPA-CNPDIA; USP-IFSC.
Título: | Reversible structural changes in met Hb and met Mb induced by hydration degree: a quantitative ESR study.
Ano de publicação: | 1990
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.
Páginas: | p.144.
Série: | (SBBq Annual Meeting, 19).
Idioma: | Inglês
Notas: | Ref.C-33.
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?).
Palavras-Chave: | Change; Degree; ESR; Hydration; Methemoglobin; Metmyoglobin; Structural; Study.
Categoria do assunto: | --
Registro original: | Embrapa Instrumentação (CNPDIA)
Exemplares: | CNPDIA - (5219-1) - UPC - SP - -- - PROCI-90.00030 -  - 1990.00030 - DIS