Abstract
For modelling cytochrome P450-catalyzed reactions, an artificial hemoprotein was designed. Upon complex formation of human serum albumin with iron protoporphyrine IX, there occurred the incorporation of heme into the protein and formation of a specific complex with the albumin to heme molar ratio 2:1. The apparent dissociation constant Kd of the complex, as determined by optical absorption spectroscopic technique, was 1.9 +/- 0.4 M-6. Based on spectral studies and molecular modelling of the complex spatial structure, it was assumed that His 31 or His 90 may be the most probable 5th ligand for the heme iron. The artificial hemoprotein was able to catalyze (in the presence of riboflavin as electron carrier) the NADH-dependent aniline hydroxylation and dimethylaniline and amidopyrine N-demethylation. The electron transfer pathway from NADH to substrate was demonstrated. Flavin appears to serve as an input center (mediator) for the rapid transfer of electrons from NADH to heme, where substrate is oxidized. The same reactions were accomplished using riboflavin photoreduction in the hemoalbumin-riboflavin system with the unfocussed laser emission at lambda = 457.9 nm. As electron donor, metallic zinc was used. The artificial hemoprotein obtained was also able to catalyze H2O2-dependent oxidase reactions.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: 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.