Abstract
The pH dependence in the range 3--7 of the optical absorption and electron paramagnetic resonance of the nitric oxide adduct of ferrous Aplysia myoglobin is reported. Optical spectra in the Soret region show a transition between two conformers with an apparent pK in the range 3.5--5 depending on the presence of carboxylic anions as third component. In the same pH range, the EPR spectrum undergoes a change from a 9-line to a 3-line hyperfine pattern in the g. region, similar to that reported for synthetic heme derivatives and for other hemoproteins. The structural interpretation of the pH-induced transition experienced by Aplysia myoglobin nitric oxide is that of a proton-linked cleavage of the proximal bond as suggested by several lines of evidence. Temperature-jump measurements allowed an estimation of the relaxation time for the process, which is of the order of 0.3 ms at 25 degrees C.
| Original language | English |
|---|---|
| Pages (from-to) | 5383-5386 |
| Number of pages | 4 |
| Journal | Journal of Biological Chemistry |
| Volume | 256 |
| Issue number | 11 |
| Publication status | Published - Jun 10 1981 |
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ASJC Scopus subject areas
- Biochemistry
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Equilibrium and kinetic evidence for a transition between six- and five-coordinate ferrous heme in the nitric oxide derivative of Aplysia myoglobin. / Ascenzi, P.; Giacometti, G. M.; Antonini, E.; Rotilio, G.; Brunori, M.
In: Journal of Biological Chemistry, Vol. 256, No. 11, 10.06.1981, p. 5383-5386.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Equilibrium and kinetic evidence for a transition between six- and five-coordinate ferrous heme in the nitric oxide derivative of Aplysia myoglobin.
AU - Ascenzi, P.
AU - Giacometti, G. M.
AU - Antonini, E.
AU - Rotilio, G.
AU - Brunori, M.
PY - 1981/6/10
Y1 - 1981/6/10
N2 - The pH dependence in the range 3--7 of the optical absorption and electron paramagnetic resonance of the nitric oxide adduct of ferrous Aplysia myoglobin is reported. Optical spectra in the Soret region show a transition between two conformers with an apparent pK in the range 3.5--5 depending on the presence of carboxylic anions as third component. In the same pH range, the EPR spectrum undergoes a change from a 9-line to a 3-line hyperfine pattern in the g. region, similar to that reported for synthetic heme derivatives and for other hemoproteins. The structural interpretation of the pH-induced transition experienced by Aplysia myoglobin nitric oxide is that of a proton-linked cleavage of the proximal bond as suggested by several lines of evidence. Temperature-jump measurements allowed an estimation of the relaxation time for the process, which is of the order of 0.3 ms at 25 degrees C.
AB - The pH dependence in the range 3--7 of the optical absorption and electron paramagnetic resonance of the nitric oxide adduct of ferrous Aplysia myoglobin is reported. Optical spectra in the Soret region show a transition between two conformers with an apparent pK in the range 3.5--5 depending on the presence of carboxylic anions as third component. In the same pH range, the EPR spectrum undergoes a change from a 9-line to a 3-line hyperfine pattern in the g. region, similar to that reported for synthetic heme derivatives and for other hemoproteins. The structural interpretation of the pH-induced transition experienced by Aplysia myoglobin nitric oxide is that of a proton-linked cleavage of the proximal bond as suggested by several lines of evidence. Temperature-jump measurements allowed an estimation of the relaxation time for the process, which is of the order of 0.3 ms at 25 degrees C.
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UR - http://www.scopus.com/inward/citedby.url?scp=0019877017&partnerID=8YFLogxK
M3 - Article
C2 - 6263876
AN - SCOPUS:0019877017
VL - 256
SP - 5383
EP - 5386
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 11
ER -