A model for the origin of stable protocells in a primitive alkaline ocean.

When a mixture of the eighteen proteinous amino acids are suitably heated in the dry state with seawater salts, a copolyamino acid results. One fraction of this polymer is found, through isoelectric focusing, to consist of a mixture of acidic and basic proteinoids, each of sharply limited heterogeneity. When one fraction of the seawater proteinoid is dissolved in hot water, and the solution is cooled, proteinoid microspheres result. These have properties in common with simpler types, but also stable at pH values to 9, in common with microspheres prepared by mixing acidic and basic proteinoids. These processes thus constitute a simple model for the origin of a protocell stable in a primitive alkaline ocean.