Monitoring the pH-Dependent Oximation of Methyl Ethyl Ketone and Benzaldehyde by in situ Fourier Transform IR Spectroscopy in a Heterogeneous Liquid–Liquid Two-Phase System

2009 ◽  
Vol 42 (2) ◽  
pp. 67-72 ◽  
Author(s):  
György Keglevich ◽  
István Csontos ◽  
Nikolett Szilágyi
Keyword(s):  
Fourier Transform ◽  
Ir Spectroscopy ◽  
Methyl Ethyl Ketone ◽  
Phase System ◽  
Methyl Ethyl ◽  
Two Phase ◽  
Fourier Transform Ir Spectroscopy ◽  
Fourier Transform Ir ◽  
Ph Dependent

Time-resolved FTIR study of CO recombination with horseradish peroxidase

2008 ◽  
Vol 36 (6) ◽  
pp. 1165-1168 ◽  
Author(s):  
Amandine Maréchal ◽  
W. John Ingledew ◽  
Peter R. Rich
Keyword(s):  
Fourier Transform ◽  
Ir Spectroscopy ◽  
Horseradish Peroxidase ◽  
Rate Constants ◽  
Recombination Rate ◽  
Thermal Equilibrium ◽  
Time Resolved ◽  
Fourier Transform Ir Spectroscopy ◽  
Rapid Scan ◽  
Fourier Transform Ir

Vibrational changes associated with CO recombination to ferrous horseradish peroxidase were investigated by rapid-scan FTIR (Fourier-transform IR) spectroscopy in the 1200–2200 cm−1 range. At pH 6.0, two conformers of bound CO are present that appear as negative bands at 1905 and 1934 cm−1 in photolysis spectra. Their recombination rate constants are identical, confirming that they arise from two substates of bound CO that are in rapid thermal equilibrium, rather than from heterogeneous protein sites. A smaller positive band at 2134 cm−1 also appears on photolysis and decays with the same rate constant, indicative of an intraprotein geminate site involved in recombination or, possibly, a weak-affinity surface CO-binding site. Other signals arising from protein and haem in the 1700–1200 cm−1 range can also be time-resolved with similar kinetics.

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