The purpose of this work is to highlight the ability of a pre-biotic system of activation/polymerization/depolymerization ( APD) of amino acids to have non-racemic fixed points, similarly to Frank's model, and thus to evolve spontaneously toward homochirality. Chemical kinetic simulations of reaction sets, from simple isolated polymerization systems to complete APD systems in presence of inversion reactions, are developed in order to understand the mechanisms of amplification of asymmetry. The results emphasize the emergence of autocatalysis thanks to the synergetic action between epimer-ization and APD reactions, allowing spontaneous symmetry breaking from racemic state. The APD system appears to be an original nonequilibrium chemical system model, as an extension of the Frank's model based on prebiotically relevant chemical reactions.