Mechanisms of electron transfer from sulfite to horseradish peroxidase-hydroperoxide compounds

T AraisoI Yamazaki


Using a rapid-scan spectrophotometer equipped with a stopped-flow apparatus, reactions of sulfite with compounds I and II of two horseradish peroxidase isoenzymes A and C were investigated. The direct two-electron reduction of peroxidase compound I by sulfite occurred at acidic pH but the mechanism gradually changed to the two-step reduction with the intermediate formation of compound II as the pH increased. The pH at which the one- and two-electron changes occurred at the same speed was 4.5 for peroxidase A and 7.7 for peroxidase C. A new peroxidase intermediate was found in the reaction between peroxidase compound II and sulfite. The sulfite compound showed a characteristic absorption band at 850 nm and the optical spectrum was similar to that of isoporphyrins but was quite different from that of sulfhemoproteins. The rate (k) of conversion from the sulfite-compound II complex to the sulfite compound was proportional to the concentration of H+ and the log k vs. pH plot for peroxidase A moved to the acidic side by 1.1 pH unit from that for peroxidase C.


Jul 1, 1975·Archives of Biochemistry and Biophysics·H YamadaI Yamazaki
Feb 1, 1968·Biochimica Et Biophysica Acta·A W NicholD B Morell
Jun 14, 1972·Journal of the American Chemical Society·L P HagerJ C Martin
Jan 1, 1973·Archives of Biochemistry and Biophysics·H Yamazaki, I Yamazaki
Dec 1, 1974·Archives of Biochemistry and Biophysics·H Yamada, I Yamazaki
Mar 1, 1971·Proceedings of the National Academy of Sciences of the United States of America·D DolphinR H Felton
Sep 16, 1970·Biochimica Et Biophysica Acta·F Björkstén
Aug 1, 1958·Biochimica Et Biophysica Acta·D KEILIN, P NICHOLLS
Nov 1, 1961·The Biochemical Journal·P NICHOLLS
Feb 1, 1961·The Biochemical Journal·A S Brill, R J Williams


Jul 27, 2001·Journal of Biological Inorganic Chemistry : JBIC : a Publication of the Society of Biological Inorganic Chemistry·A N HinerM Acosta
Jan 1, 1990·Mutation Research·D A PaganoA A Stark
Jan 1, 1990·Pharmacology & Therapeutics·P R Ortiz de Montellano
May 27, 2010·The Journal of Biological Chemistry·Kalina RanguelovaRonald P Mason
Mar 30, 2010·Environmental Health Perspectives·Kalina RanguelovaRonald P Mason
Dec 1, 1985·Environmental Health Perspectives·I YamazakiM Nakamura
Jan 1, 1985·Food Additives and Contaminants·R Walker
Jun 30, 2012·Journal of Porphyrins and Phthalocyanines·Sandra C MwakwariKevin M Smith
Jan 20, 2011·Magnetic Resonance in Chemistry : MRC·Kalina Ranguelova, Ronald P Mason
Sep 5, 1985·Journal of Molecular Biology·I Fita, M G Rossmann
Apr 15, 1982·Archives of Biochemistry and Biophysics·H P Misra, P M Squatrito
Aug 19, 2015·Dalton Transactions : an International Journal of Inorganic Chemistry·Jagannath Bhuyan
Feb 14, 2012·Free Radical Biology & Medicine·Kalina RanguelovaRonald P Mason
Jun 20, 2012·Neurochemistry International·Erdogan KocamazVural Kucukatay
Jul 1, 1980·Journal of Dairy Science·H E Swaisgood, P Abraham

Related Concepts

Respiratory Chain
Hydrogen-Ion Concentration

Trending Feeds


Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Neural Activity: Imaging

Imaging of neural activity in vivo has developed rapidly recently with the advancement of fluorescence microscopy, including new applications using miniaturized microscopes (miniscopes). This feed follows the progress in this growing field.

The Tendon Seed Network

Tendons are rich in the extracellular matrix and are abundant throughout the body providing essential roles including structure and mobility. The transcriptome of tendons is being compiled to understand the micro-anatomical functioning of tendons. Discover the latest research pertaining to the Tendon Seed Network here.

Myocardial Stunning

Myocardial stunning is a mechanical dysfunction that persists after reperfusion of previously ischemic tissue in the absence of irreversible damage including myocardial necrosis. Here is the latest research.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.


Incretins are metabolic hormones that stimulate a decrease in glucose levels in the blood and they have been implicated in glycemic regulation in the remission phase of type 1 diabetes. Here is the latest research.

Chromatin Regulation and Circadian Clocks

The circadian clock plays an important role in regulating transcriptional dynamics through changes in chromatin folding and remodelling. Discover the latest research on Chromatin Regulation and Circadian Clocks here.

Long COVID-19

“Long Covid-19” describes illness in patients who are reporting long-lasting effects of the SARS-CoV-19 infection, often long after they have recovered from acute Covid-19. Ongoing health issues often reported include low exercise tolerance and breathing difficulties, chronic tiredness, and mental health problems such as post-traumatic stress disorder and depression. This feed follows the latest research into Long Covid.

Spatio-Temporal Regulation of DNA Repair

DNA repair is a complex process regulated by several different classes of enzymes, including ligases, endonucleases, and polymerases. This feed focuses on the spatial and temporal regulation that accompanies DNA damage signaling and repair enzymes and processes.