You are here : HOME > Research field > Oxidative stress
Oxidative stress is caused by an imbalance between the production of reactive oxygen and a biological system's ability to readily detoxify the reactive intermediates or easily repair the resulting damage. In humans, oxidative stress is involved in many diseases, such as atherosclerosis
, Parkinson's disease
, Heart Failure
, Myocardial Infarction
, Alzheimer's disease
and chronic fatigue syndrome.
Many molecule families are involved in this phenomenon :
Cyclooxygenase (COX) is an enzyme that is responsible for formation of important biological mediators called prostanoids, including prostaglandins, prostacyclin and thromboxane. COX converts arachidonic acid to prostaglandin H2 (PGH2), the precursor of the series-2 prostanoids.
Currently three COX isoenzymes are known: COX-1, COX-2, and COX-3.
Heat shock proteins (HSP) are a class of functionally related proteins whose expression is increased when cells are exposed to elevated temperatures or other stress. The dramatic upregulation of the heat shock proteins is a key part of the heat shock response and is induced primarily by heat shock factor (HSF1 and HSF2). HSPs are named according to their molecular weight for eukaryotic proteins (prokaryotic equivalents) :
Hsp10 (GroES), Hsp20, Hsp22, Hsp25, Hsp27 (GrpE), Hsp30, Hsp40 (DnaJ), Hsp47, Hsp60 (GroEL), Hsp65, Hsp70 (DnaK), Hsp70b, Hsp71, Hsp90, Hsp104, Hsp105, Hsp110 (ClpB, ClpX)
Heme oxygenase cleaves the heme ring at the alpha-methene bridge to form either biliverdin or, if the heme is still attached to a globin, verdoglobin. Biliverdin is subsequently converted to bilirubin by biliverdin reductase.
There are three known isoforms of heme oxygenase.
Heme oxygenase 1 (HO-1) is an inducible isoform in response to stress such as oxidative stress, hypoxia, heavy metals, cytokines, etc.
Heme oxygenase 2 (HO-2) is a constitutive isoform which is expressed under homeostatic conditions.
Heme oxygenase 3 (HO-3) is not catalytically active, but is thought to work in oxygen sensing.
Selenium binding protein (SBP),
Glutathion peroxidase is the general name of an enzyme family with peroxidase activity whose main biological role is to protect the organism from oxidative damage. By catalyzing the following reaction : GS–SG + NADPH + H+ <=> 2 GSH + NADP+
Nitric Oxide Synthase (NOS) is an enzyme family in the body that contributes to transmission from one neuron to another (nNOS), to the immune system (iNOS) and to endothelial cells (eNOS).
Superoxide dismutases (SOD) are a class of enzymes that catalyze the dismutation of superoxide into oxygen and hydrogen peroxide.
Flavin Reductase is an enzyme that catalyzes the chemical reaction : reduced riboflavin + NADP+ riboflavin + NADPH + H+
Cytochrome P450 is an enzyme that catalyzes the monooxygenase reaction : RH + O2 + 2H+ + 2e– <=> ROH + H2O