Abstract |
The equilibrium and kinetics of methemoglobin conversion to hemichrome induced by dehydration were investigated by visible absorption spectroscopy. Below about 0.20 g water per g hemoglobin only hemichrome was present in the sample; above this value, an increasing proportion of methemoglobin appeared with the increase in hydration. The transition between the two derivatives showed a time-dependent biphasic behavior and was observed to be reversible. The rates obtained for the transition of methemoglobin to hemichrome were 0.31 and 1.93 min-1 and for hemichrome to methemoglobin 0.05 and 0.47 min-1. We suggest that hemichrome is a reversible conformational state of hemoglobin and that the two rates observed for the transition between the two derivatives reflect the alpha- and beta-chains of hemoglobin.
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Authors | M F Colombo, R Sanches |
Journal | Biophysical chemistry
(Biophys Chem)
Vol. 36
Issue 1
Pg. 33-9
(May 1990)
ISSN: 0301-4622 [Print] Netherlands |
PMID | 2207271
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Hemeproteins
- hemichrome
- Water
- Methemoglobin
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Topics |
- Desiccation
- Hemeproteins
(chemistry)
- Humans
- Kinetics
- Methemoglobin
(chemistry)
- Protein Conformation
(drug effects)
- Spectrophotometry
- Water
(pharmacology)
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