Department of Medical Sciences and Biotechnology, Vascular Biology and Mass Spectrometry Laboratory, Sapienza University of Roma, Latina, Italy.
Chem Phys Lipids. 2011 Sep;164(6):457-68. doi: 10.1016/j.chemphyslip.2011.06.006. Epub 2011 Jun 15.
Cholesterol has many functions, including those that affect biophysical properties of membranes, and is a precursor to hormone synthesis. These actions are governed by enzymatic pathways that modify the sterol nucleus or the isooctyl tail. The addition of oxygen to the cholesterol backbone produces its derivatives known as oxysterols. In addition to having an enzymatic origin, oxysterols can be formed in the absence of enzymatic catalysis in a pathway usually termed "autoxidation," which has been known for almost a century and observed under various experimental conditions. Autoxidation of cholesterol can occur through reactions initiated by free radical species, such as those arising from the superoxide/hydrogen peroxide/hydroxyl radical system and by non-radical highly reactive oxygen species such as singlet oxygen, HOCl, and ozone. The susceptibility of cholesterol to non-enzymatic oxidation has raised considerable interest in the function of oxysterols as biological effectors and potential biomarkers for the non-invasive study of oxidative stress in vivo.
胆固醇具有多种功能，包括影响膜的生物物理性质和作为激素合成前体的功能。这些作用由酶促途径控制，这些途径可以修饰甾醇核或异辛基尾部。胆固醇主链上加氧产生其衍生物，称为氧化固醇。除了具有酶促来源外，氧化固醇可以在没有酶催化的情况下形成通常称为“自动氧化”的途径中，该途径已经存在了近一个世纪，并在各种实验条件下观察到。胆固醇的自动氧化可以通过自由基物种引发的反应发生，例如超氧化物/过氧化氢/羟基自由基系统产生的自由基和非自由基高反应性氧物种，如单线态氧、HOCl 和臭氧。胆固醇对非酶促氧化的易感性引起了人们对氧化固醇作为生物效应物和潜在生物标志物的功能的极大兴趣，可用于非侵入性研究体内氧化应激。
