Journal article
Thermochromism of heme adducts of Glycera hemoglobin and some other monomeric heme proteins
Journal of inorganic biochemistry, v 39(4), pp 351-369
1990
PMID: 2167947
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
The thermally induced difference spectra of myoglobin (Mb) and
Glycera dibranchiata hemoglobin (Hb
m) derivatives and of cytochrome-
c were recorded between 4° and 30°C in the 390–750 nm range. Thermodynamic parameters were estimated and upper and lower temperature limiting spectra were deduced for the various heme protein derivatives' equilibria. The effective iron d-electron population divides the hemes broadly into two different groups of behavior type. In the first group, Hb
m(III)N
3, Hb
m(III), Mb(III)(H
2O), and Cytc(III) show equilibria between two spin states. The weakest coupling between the heme and the globin occurs among the second group, for Hb
m(II)CO and Mb(II)CO, which in the higher temperature limit undergoes averaging of the carbonyl tilt, while an axially elongated geometry is probably accessed for Hb
m(II)NO and Mb(II) NO. Examples of the less common situation of increased absorption intensity and/or low-spin states at higher temperature were found in both groups. In the case of the methyl thioglycolate low-spin adducts of Hb
m (III), an acid/base equilibrium involviong thioglycolate deprotonation occurs. Apparent enthalpy-entropy compensation is exhibited by all these heme derivatives, and it is suggested that the ΔH° and ΔS° values relate to the intimacy of coupling between the heme structure and the solvent-dependent microconformation of the globin.
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Details
- Title
- Thermochromism of heme adducts of Glycera hemoglobin and some other monomeric heme proteins
- Creators
- Joseph J. Stephanos - Drexel UniversityAnthony W. Addison - Drexel University
- Publication Details
- Journal of inorganic biochemistry, v 39(4), pp 351-369
- Publisher
- Elsevier
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Chemistry
- Web of Science ID
- WOS:A1990DQ81300008
- Scopus ID
- 2-s2.0-0025322765
- Other Identifier
- 991019173791104721
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InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Web of Science research areas
- Biochemistry & Molecular Biology
- Chemistry, Inorganic & Nuclear