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Contribution of Cytochromes and Proteins to the Effect of Ascorbic Acid on Artificial and Microsomal Hydroxylation Systems Containing Oxygen and Hydrogen Peroxide

Overview
Journal Biochem J
Specialty Biochemistry
Date 1978 Mar 15
PMID 25655
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Abstract

Hydroxylation systems containing cytochromes, proteins and ascorbic acid were studied at physiological pH (7.4) under O2 or N2 with added H2O2. Proteins inhibited aromatic hydroxylation of p-nitrophenol or oxidative demethylation of ethylmorphine in ascorbic acid-containing systems incubated under O2, but strongly activated the systems containing H2O2. Cytochrome c and partially purified cytochrome P-450 from rat liver microsomal preparations activated the system in either O2 or H2O2. The systems needed ascorbic acid (or other enol structures) for activation. Cytochrome iron participated probably in the activation of O2, whereas cytochrome protein participated in a free radical activation of H2O2 (or of O2).

References
1.
Chrastil J, Wilson J . A sensitive colorimeter method for formaldehyde. Anal Biochem. 1975; 63(1):202-7. DOI: 10.1016/0003-2697(75)90205-5. View

2.
Rahimtula A, OBrien P . Hydroperoxide dependent O-dealkylation reactions catalyzed by liver microsomal cytochrome P450. Biochem Biophys Res Commun. 1975; 62(2):268-75. DOI: 10.1016/s0006-291x(75)80133-1. View

3.
Nash T . The colorimetric estimation of formaldehyde by means of the Hantzsch reaction. Biochem J. 1953; 55(3):416-21. PMC: 1269292. DOI: 10.1042/bj0550416. View

4.
UDENFRIEND S, CLARK C, Axelrod J, Brodie B . Ascorbic acid in aromatic hydroxylation. I. A model system for aromatic hydroxylation. J Biol Chem. 1954; 208(2):731-9. View

5.
GILLETTE J, Brodie B, La Du B . The oxidation of drugs by liver microsomes: on the role of TPNH and oxygen. J Pharmacol Exp Ther. 1957; 119(4):532-40. View