Ad
related to: lipid peroxidation and antioxidant protection pdf form example format
Search results
Results From The WOW.Com Content Network
Lipid peroxidation, or lipid oxidation, is a complex chemical process that leads to oxidative degradation of lipids, [1] resulting in the formation of peroxide and hydroperoxide derivatives. [2] It occurs when free radicals , specifically reactive oxygen species (ROS), interact with lipids within cell membranes , typically polyunsaturated fatty ...
The autoxidation of unsaturated fatty acids causes them to crosslink to form polymers. [16] This phenomenon has been known since antiquity and forms the basis of drying oils, which were traditionally used to make many varnishes and paints. [17] Linseed oil, which is rich in polyunsaturated fats, is a prime example.
It has been claimed [by whom?] that the α-tocopherol form is the most important lipid-soluble antioxidant, and that it protects membranes from oxidation by reacting with lipid radicals produced in the lipid peroxidation chain reaction. [82] [85] This removes the free radical intermediates and prevents the propagation reaction from continuing.
Kinetic isotope effect is observed when molecules containing heavier isotopes of the same elements (for example, deuterium for hydrogen) engage in a chemical reaction at a slower rate. Deuterium-reinforced lipids can be used for protecting living cells by slowing the chain reaction of lipid peroxidation. [1]
Glutathione peroxidase 4 (GPx4) has a high preference for lipid hydroperoxides; it is expressed in nearly every mammalian cell, though at much lower levels. Glutathione peroxidase 2 is an intestinal and extracellular enzyme, while glutathione peroxidase 3 is extracellular, especially abundant in plasma. [ 4 ]
The cytosolic acetyl-CoA can also condense with acetoacetyl-CoA to form 3-hydroxy-3-methylglutaryl-CoA which is the rate-limiting step controlling the synthesis of cholesterol. [16] Cholesterol can be used as is, as a structural component of cellular membranes, or it can be used to synthesize steroid hormones , bile salts , and vitamin D .
The peroxide value is defined as the amount of peroxide oxygen per 1 kilogram of fat or oil. Traditionally this was expressed in units of milliequivalents, although in SI units the appropriate option would be in millimoles per kilogram (N.B. 1 milliequivalents = 0.5 millimole; because 1 mEq of O2 =1 mmol/2 of O2 =0.5 mmol of O2, where 2 is valence).
Alpha-tocopherol is a fat-soluble antioxidant functioning within the glutathione peroxidase pathway, [15] and protecting cell membranes from oxidation by reacting with lipid radicals produced in the lipid peroxidation chain reaction. [3] [16] This removes the free radical intermediates and prevents the oxidation reaction from continuing.