An Individual Amino Acid as a Possible Prebiotic Catalyst

Better understanding how reactions have been catalyzed in the prebiotic world is important for better realizing how enzymes have evolved. The dominant hypothesis is that the first catalyst was an RNA molecule. It was also assumed that amyloid fibrils, self-assembled by peptides or proteins, served as the first catalysts. However, debate still exists regarding which process occurred first: the polymerization of RNA or the synthesis of proteins. Here, we show that an individual amino acid, L-3,4-dihydroxyphenylalanine (DOPA), can act as a catalyst. This amino acid is the main constituent of mussel adhesion proteins that function in harsh conditions very similar to plausible prebiotic conditions. By tracing the hydrolysis of two compounds, p-nitrophenylacetate and acetylcholine, we showed that DOPA catalyzes a reaction; we suggest its role as a prebiotic catalyst.