Abstract
Absorption spectroscopy measurements of the binding of aromatic donors and competitive inhibitors to horseradish peroxidase indicate that they are bound to the enzyme through hydrophobic forces and hydrogen bonding. Nuclear magnetic resonance experiments show that the minimal distances between the enzyme iron and the protons of a typical donor, p-cresol, are 7.0 ± 0.5, 7.7 ± 0.5 and 8.5 ± 0.5 Å, for the ortho-, meta- and methyl-protons, respectively. A model for the binding of aromatic donors to horseradish peroxidase based on this result is presented. It is proposed that the aromatic ring is attached to a hydrophobic region in the protein interior and the phenol oxygen is hydrogen-bonded to the pyrrolic nitrogen of the iron-coordinated histidine. This structure is compatible with the proton-iron distances measured and offers an intramolecular path for electron conduction from donor to heme analogous to that proposed by Winfield for the peroxidases.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
