RUBISCO CONTENDER. “The Rubisco protein…is responsible for atmospheric carbon fixation, literally building the biosphere out of thin air. This molecule, one of the most abundant proteins on Earth, is responsible for extracting about a hundred Gigatons of carbon from the atmosphere each year. This is ≈10 times more than all the carbon dioxide emissions made by humanity from car tailpipes, jet engines, power plants and all of our other fossil-fuel-driven technologies.”
http://book.bionumbers.org/how-big-is-the-average-protein/