Departamento de Química Orgánica e Inorgánica, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain.
Chirality. 2012 Nov;24(11):894-908. doi: 10.1002/chir.22028. Epub 2012 Jun 7.
Mirror symmetry breaking is ubiquitous in our visible universe taking place in elementary particles, atoms, and molecules. Molecular chirality is not biogenic in itself, although its detection is often considered a biosignature, a conjecture inferred from the fact that we do not know life devoid of homochirality. The question of whether there is a connection between the cosmic preference for one enantiomer, as imposed by the weak force, and the single chirality displayed on Earth is vividly debated. This article gives a glimpse on the origin of asymmetry from a cosmological perspective and on physical transformations that lead to an enantiomeric imbalance, leaving chemical reactions essentially aside. These processes are more plausible as sources of prebiotic chirality than asymmetric amplifications requiring unnatural substrates and conditions and fighting against racemization. The latter may actually be a friend, not foe, and a driving force for enantioselection.
镜像对称破缺在我们可见的宇宙中无处不在，存在于基本粒子、原子和分子中。分子手性本身并非生物起源，尽管其检测通常被认为是生物特征，这一推测是基于我们不知道没有手性的生命这一事实。宇宙中弱相互作用对单一对映体的偏好与地球上显示的单一手性之间是否存在联系，这是一个激烈争论的问题。本文从宇宙学的角度探讨了不对称性的起源，以及导致对映体失衡的物理转化，基本上不考虑化学反应。这些过程作为前生物手性的来源比需要非自然底物和条件并与外消旋作用作斗争的不对称放大更合理。后者实际上可能是手性选择的朋友而非敌人，也是驱动力。
