The process of adding oxygen to a compound, dehydrogenation or increasing the electro-negative charge.
The act of oxidizing or state of being oxidized. Chemically it consists in the increase of positive charges on an atom or the loss of negative charges. Most biological oxidations are accomplished by the removal of a pair of hydrogen atoms (dehydrogenation) from a molecule. Such oxidations must be accompanied by reduction of an acceptor molecule. Univalent o. indicates loss of one electron; divalent o., the loss of two electrons.
The chemical process of removing electrons from an element or compound, frequently together with the removal of hydrogen ions (H+). The reverse process, the addition of electrons or hydrogen, is reduction.
A chemical reaction involving the addition or combination of oxygen with another material.
The process of oxygen combining with other substances, resulting in heat production and energy.
A gain of oxygen, a loss of hydrogen, or the direct loss of electrons by an atom or substance.
Loss of electrons from a compound (or element) in a chemical reaction. When one compound is oxidized, another compound is reduced. That is, the other compound must “pick up” the electrons which the first has lost.
The chemical combining of oxygen with other substances as during burning.
The action of making oxides by combining with oxygen or removing hydrogen.
The chemical process by which a substance combines with oxygen, resulting in a change to another form.
The removal of electrons using oxygen as the electron acceptor. The process may not always involve an enzyme. It may occur spontaneously, and when this occurs, it is called autoxidation. In food, autoxidation occurs and is responsible for the deterioration of food quality. The discoloration of red meat upon exposure to air at room temperature is an indication of the autoxidation process. The off odor that accompanies this discoloration is the result of the autoxidation of the fatty acids in the meat fat. In living systems, the process of autoxidation is suppressed to a large extent because the products of this oxidation, fatty acid peroxides, can be very damaging. Peroxides denature proteins, rendering them inactive and attacking the DNA in the nucleus and mitochondria, resulting in base pair deletions or breaks in the DNA, which, in turn, result in mutations or errors in this DNA. In the nucleus, these breaks or deletions can be repaired. In the aging animal, the repair mechanism loses its efficiency. One of the characteristics of aged cells is the loss of its DNA repair ability. Mitochondria have little DNA repair capability, so base pair deletions, substitutions, or insertions occurring as a result of free radical attack cannot be reversed. Fortunately, there are many mitochondria in each cell so that if a few are damaged in this way, the effect is not as devastating as happens with unrepaired DNA damage in the nucleus.
Reactions in which electrons are lost by one reactant and gained by another.
Addition of oxygen, removal of hydrogen, or removal of electrons from an element or com¬ pound. Always accompanied by reduction (gain of electrons) of the oxidizing agent. The combination of simultaneous oxidation and reduction reactions is often termed an oxidation-reduction (redox) reaction. These occur commonly in blood when hemoglobin is oxygenated (oxidized), and then again when oxygen is delivered to the tissues (reduction). In the environment, organic matter is oxidized to more stable substances.
The combination of a substance with oxygen. Chemical oxidation involves changes in the electrical charge of the atoms being combined with oxygen. Biological oxidation occurs when enzymes metabolize food, causing a release of energy. Most biological oxidations occur with the removal of a pair of hydrogen atoms from a molecule in a process called dehydrogenation.