Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Search research articles

Related Experiment Videos

alpha, beta-Dihydroxyisovalerate dehydratase. A superoxide-sensitive enzyme.

C F Kuo, T Mashino, I Fridovich

The Journal of Biological Chemistry

|April 5, 1987

Summary

Oxygen inactivates a key enzyme in Escherichia coli, reducing its activity. Reactivation occurs under anaerobic conditions, suggesting a protective mechanism against oxidative stress and bacteriostatic effects.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Clustering of comorbidities and associated outcomes in people with osteoarthritis - A UK Clinical Practice Research Datalink study.

Osteoarthritis and cartilage·2022

Same author

Trends in incidence and prevalence of osteoarthritis in the United Kingdom: findings from the Clinical Practice Research Datalink (CPRD).

Osteoarthritis and cartilage·2020

Same author

Comorbidity in multiple sclerosis: its temporal relationships with disease onset and dose effect on mortality.

European journal of neurology·2019

Same author

Preventing arteriovenous shunt failure in hemodialysis patients: a population-based cohort study.

Journal of thrombosis and haemostasis : JTH·2018

Same author

Epilepsy and associated mortality in patients with multiple sclerosis.

European journal of neurology·2018

Same author

Clinical bandings of Patient-Oriented Eczema Measure scores among Japanese patients with atopic eczema.

The British journal of dermatology·2017

Area of Science:

Microbiology
Biochemistry
Enzymology

Background:

Aerobic Escherichia coli exposed to oxidative agents like paraquat or plumbagin show reduced alpha, beta-dihydroxyisovalerate dehydratase activity.
This enzyme inactivation is dependent on oxygen and is exacerbated by chloramphenicol, indicating a role for reactive oxygen species and protein synthesis.

Purpose of the Study:

To investigate the mechanism by which oxygen and oxidative agents affect alpha, beta-dihydroxyisovalerate dehydratase activity in Escherichia coli.
To determine if superoxide dismutase or catalase plays a role in protecting the enzyme from oxygen-induced inactivation.

Main Methods:

Incubation of aerobic Escherichia coli with paraquat or plumbagin.
Measurement of alpha, beta-dihydroxyisovalerate dehydratase activity in cell extracts.
Assessment of enzyme activity under aerobic and anaerobic conditions, with and without chloramphenicol.
Immunoprecipitation to selectively remove superoxide dismutase or catalase, followed by activity assays.
Addition of exogenous superoxide dismutase or catalase.

Main Results:

Paraquat and plumbagin significantly reduced dehydratase activity in aerobic E. coli, an effect absent under anaerobic conditions.
Inhibition of protein synthesis with chloramphenicol exacerbated the inactivation, while transfer to anaerobic conditions led to enzyme activity recovery.
Selective removal of superoxide dismutase, but not catalase, increased enzyme instability; exogenous superoxide dismutase reversed this effect.

Conclusions:

The alpha, beta-dihydroxyisovalerate dehydratase enzyme is inactivated by oxygen, likely via superoxide radicals.
Escherichia coli possesses a mechanism to reactivate the enzyme under anaerobic conditions.
Superoxide dismutase plays a crucial role in protecting the dehydratase from oxygen-mediated inactivation, potentially explaining the bacteriostatic effects of oxygen and paraquat.

Related Experiment Videos