Infrared-monitored flash-photolysis of carboxymyoglobin
An infrared-monitored flash-photolysis apparatus capable of measuring absorbance changes to 10$\sp{-3}$OD over a time range from 10$\mu$s to 10s is described. Measurements made on this apparatus, combined with slower measurements made on a Fourier-transform infrared spectrometer, of the CO-rebinding...
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ftunivillidea:oai:www.ideals.illinois.edu:2142/22089 2023-05-15T18:26:49+02:00 Infrared-monitored flash-photolysis of carboxymyoglobin Vittitow, Joseph Lawrence 1989 http://hdl.handle.net/2142/22089 eng eng http://hdl.handle.net/2142/22089 (UMI)AAI9011062 AAI9011062 Copyright 1989 Vittitow, Joseph Lawrence Physics Molecular Biophysics General text 1989 ftunivillidea 2014-01-12T19:38:25Z An infrared-monitored flash-photolysis apparatus capable of measuring absorbance changes to 10$\sp{-3}$OD over a time range from 10$\mu$s to 10s is described. Measurements made on this apparatus, combined with slower measurements made on a Fourier-transform infrared spectrometer, of the CO-rebinding kinetics of the A$\sb0$, A$\sb1$, and A$\sb3$ conformations of sperm-whale myoglobin (Mb) at atmospheric pressure and neutral pH are reported. The A$\sb0$, A$\sb1$, and A$\sb3$ rebinding kinetics are shown to be non-exponential and parameterized by activation-enthalpy distributions differing in prefactor $k\sb0\ (\log(k\sb0/s)$ = 10.8, 9.3, and 9.8 for the A$\sb0$, A$\sb1$, and A$\sb3$ conformations, respectively) and peak activation-enthalpy $H\sb{p}\ (H\sb{p} = 10.4$, 9.6, and 17.6 kJ/M, respectively). CO-rebinding kinetics of MbCO ensembles prepared along different paths in the pressure-temperature plane ("freeze" and "squeeze-freeze-release" ensembles) monitored at two frequencies within the A$\sb1$ band are also reported. No differences between kinetics monitored at 1943.0cm$\sp{-1}$ and 1947.5cm$\sp{-1}$, and none between the kinetics of the freeze and squeeze-freeze-release ensembles, are resolved. The large uncertainty in the determination of the peak $H\sb{p}$ of the activation-enthalpy distribution ($H\sb{p}$ = 15 (+8,$-$7)kJ/M for the squeeze-freeze-release ensemble monitored at 1943.0cm$\sp{-1}$) suggests limits of the capability of the apparatus, which are discussed in terms of time resolution. Text Sperm whale University of Illinois at Urbana-Champaign: IDEALS (Illinois Digital Environment for Access to Learning and Scholarship) |
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Open Polar |
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University of Illinois at Urbana-Champaign: IDEALS (Illinois Digital Environment for Access to Learning and Scholarship) |
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ftunivillidea |
language |
English |
topic |
Physics Molecular Biophysics General |
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Physics Molecular Biophysics General Vittitow, Joseph Lawrence Infrared-monitored flash-photolysis of carboxymyoglobin |
topic_facet |
Physics Molecular Biophysics General |
description |
An infrared-monitored flash-photolysis apparatus capable of measuring absorbance changes to 10$\sp{-3}$OD over a time range from 10$\mu$s to 10s is described. Measurements made on this apparatus, combined with slower measurements made on a Fourier-transform infrared spectrometer, of the CO-rebinding kinetics of the A$\sb0$, A$\sb1$, and A$\sb3$ conformations of sperm-whale myoglobin (Mb) at atmospheric pressure and neutral pH are reported. The A$\sb0$, A$\sb1$, and A$\sb3$ rebinding kinetics are shown to be non-exponential and parameterized by activation-enthalpy distributions differing in prefactor $k\sb0\ (\log(k\sb0/s)$ = 10.8, 9.3, and 9.8 for the A$\sb0$, A$\sb1$, and A$\sb3$ conformations, respectively) and peak activation-enthalpy $H\sb{p}\ (H\sb{p} = 10.4$, 9.6, and 17.6 kJ/M, respectively). CO-rebinding kinetics of MbCO ensembles prepared along different paths in the pressure-temperature plane ("freeze" and "squeeze-freeze-release" ensembles) monitored at two frequencies within the A$\sb1$ band are also reported. No differences between kinetics monitored at 1943.0cm$\sp{-1}$ and 1947.5cm$\sp{-1}$, and none between the kinetics of the freeze and squeeze-freeze-release ensembles, are resolved. The large uncertainty in the determination of the peak $H\sb{p}$ of the activation-enthalpy distribution ($H\sb{p}$ = 15 (+8,$-$7)kJ/M for the squeeze-freeze-release ensemble monitored at 1943.0cm$\sp{-1}$) suggests limits of the capability of the apparatus, which are discussed in terms of time resolution. |
format |
Text |
author |
Vittitow, Joseph Lawrence |
author_facet |
Vittitow, Joseph Lawrence |
author_sort |
Vittitow, Joseph Lawrence |
title |
Infrared-monitored flash-photolysis of carboxymyoglobin |
title_short |
Infrared-monitored flash-photolysis of carboxymyoglobin |
title_full |
Infrared-monitored flash-photolysis of carboxymyoglobin |
title_fullStr |
Infrared-monitored flash-photolysis of carboxymyoglobin |
title_full_unstemmed |
Infrared-monitored flash-photolysis of carboxymyoglobin |
title_sort |
infrared-monitored flash-photolysis of carboxymyoglobin |
publishDate |
1989 |
url |
http://hdl.handle.net/2142/22089 |
genre |
Sperm whale |
genre_facet |
Sperm whale |
op_relation |
http://hdl.handle.net/2142/22089 (UMI)AAI9011062 AAI9011062 |
op_rights |
Copyright 1989 Vittitow, Joseph Lawrence |
_version_ |
1766208791046520832 |