Available online at www.sciencedirect.com Physics of Life Reviews 8 (2011) 307–330 www.elsevier.com/locate/plrev Review Photochirogenesis: Photochemical models on the absolute asymmetric formation of amino acids in interstellar space Cornelia Meinert a , Pierre de Marcellus b , Louis Le Sergeant d’Hendecourt b,c , Laurent Nahon d , Nykola C. Jones e , Søren V. Hoffmann e , Jan Hendrik Bredehöft f , Uwe J. Meierhenrich a,∗ a Faculté des Sciences, UMR 6001 CNRS, LCMBA, University of Nice-Sophia Antipolis, 28 Avenue Valrose, 06108 Nice, France b Astrochimie et Origines, Institut d’Astrophysique Spatiale, UMR 8617, Université Paris-Sud, 91405 Orsay, France c CNRS, F-91405 Orsay, France d Synchrotron SOLEIL, l’Orme des Merisiers, Saint Aubin BP 48, 91192 Gif-sur-Yvette, France e Institute for Storage Ring Facilities, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark f Institute for Applied and Physical Chemistry, University of Bremen, Leobener Str. NW2, 28359 Bremen, Germany Received 4 July 2011; accepted 26 August 2011 Available online 3 September 2011 Communicated by E. Di Mauro Abstract Proteins of all living organisms including plants, animals, and humans are made up of amino acid monomers that show identical stereochemical L-configuration. Hypotheses for the origin of this symmetry breaking in biomolecules include the absolute asym- metric photochemistry model by which interstellar ultraviolet (UV) circularly polarized light (CPL) induces an enantiomeric excess in chiral organic molecules in the interstellar/circumstellar media. This scenario is supported by a) the detection of amino acids in the organic residues of UV-photo-processed interstellar ice analogues, b) the occurrence of L-enantiomer-enriched amino acids in carbonaceous meteorites, and c) the observation of CPL of the same helicity over large distance scales in the massive star-forming region of Orion. These topics are of high importance in topical biophysical research and will be discussed in this review. Further evidence that amino acids and other molecules of prebiotic interest are asymmetrically formed in space comes from studies on the enantioselective photolysis of amino acids by UV-CPL. Also, experiments have been performed on the absolute asymmetric photochemical synthesis of enantiomer-enriched amino acids from mixtures of astrophysically relevant achiral precursor molecules using UV-circularly polarized photons. Both approaches are based on circular dichroic transitions of amino acids that will be high- lighted here as well. These results have strong implications on our current understanding of how life’s precursor molecules were possibly built and how life selected the left-handed form of proteinogenic amino acids.  2011 Elsevier B.V. All rights reserved. Keywords: Amino acids; Homochirality; Enantioselective photosynthesis; Asymmetric photolysis; Origin of life; Astrochemistry * Corresponding author. Tel.: +33 49207 6177; fax: +33 49207 6151. E-mail addresses: cornelia.meinert@unice.fr (C. Meinert), pierre.demarcellus@ias.u-psud.fr (P. de Marcellus), Ldh@ias.u-psud.fr (L. Le Sergeant d’Hendecourt), laurent.nahon@synchrotron-soleil.fr (L. Nahon), nykj@phys.au.dk (N.C. Jones), vronning@phys.au.dk (S.V. Hoffmann), jhbredehoeft@uni-bremen.de (J.H. Bredehöft), uwe.meierhenrich@unice.fr (U.J. Meierhenrich). 1571-0645/$ – see front matter  2011 Elsevier B.V. All rights reserved. doi:10.1016/j.plrev.2011.08.005