Each word calls for one “ingredient” amino acid from among the list of 20 natural amino acids that make up proteins. The recoded genome reassigned four codons to non-degenerate functions, including the two recoded stop codons dedicated to encoding nonstandard, or unnatural, amino acids into protein. These nonstandard amino acids imbue proteins with multiple new properties, such as programmable biologics with reduced immunogenicity (a substance’s ability to induce an immune response in the body) or biomaterials with enhanced conductivity. In that study they encoded non-standard amino acids into protein, demonstrating a safer, controllable approach to precisely tune the half-life of protein biologics. Isaacs and Rinehart are currently acting as advisors to Pearl Bio, a Yale biotechnology spin-off that has licensed the technology for commercializing programmable biologics.