How much actin could we make for 580,000 ATPs per second? Actin is a filament composed of monomers joined together in a chain; and two such chains are wound around each other to form the filament. Each monomer has 374 amino acids, and there are 2 × 29 monomers per micrometre of actin filament. With the same ATP cost per peptide bond, the total ATP requirement per micrometre of actin is 131,000. So in principle we could make about 4.5 micrometres of actin per second.
