Planetary Minerals Catalyze Conversion of a Polycyclic Aromatic Hydrocarbon to a Prebiotic Quinone: Implications for Origins of Life

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in astrochemical environments and are disbursed into planetary environments via meteorites and extraterrestrial infall where they may interact with mineral phases to produce quinones important for origins of life. To assess the reasonableness of this process, we assessed the potential of the phyllosilicates montmorillonite (MONT) and kaolinite (KAO) and the Enhanced Mohave Mars Simulant (MMS) to catalyze conversion of the PAH anthracene (1) to the biologically important 9,10-anthraquinone (2). All substrates catalyzed conversion over the temperature range assessed (25-500 oC). Conversion rate curves were sigmoidal for MONT and KAO, but quadratic for MMS. Conversion efficiency maxima for 2 were 3.06  0.42 %, 1.15  0.13 %, and 0.56  0.039 % for MONT, KAO, and MMS, respectively. We hypothesized that differential binding and compound loss account for the conversion kinetics observed. Loss rate curves for 1 and 2 were exponential for all substrates, suggesting a pathway for wide distribution of both compounds in warmer prebiotic environments. These findings improve upon our previously reported 2 conversion efficiency on MONT and provide support for a plausible scenario in which PAH-mineral interactions can produce biological quinones in prebiotic environments.