Editing Macromolecule (section)

==== Proteins are optimised for catalysis ====
Proteins are functional macromolecules responsible for [[enzyme catalysis|catalysing]] the [[Metabolism|biochemical reaction]]s that sustain life.<ref name="Stryer_2002"/>{{Rp|3}} Proteins carry out all functions of an organism, for example photosynthesis, neural function, vision, and movement.<ref name="isbn978-1593272029">{{cite book |author = Takemura, Masaharu|title = The Manga Guide to Molecular Biology|publisher = [[No Starch Press]]|year = 2009|isbn = 978-1-59327-202-9}}</ref>

The single-stranded nature of protein molecules, together with their composition of 20 or more different amino acid building blocks, allows them to fold in to a vast number of different three-dimensional shapes, while providing binding pockets through which they can specifically interact with all manner of molecules. In addition, the chemical diversity of the different amino acids, together with different chemical environments afforded by local 3D structure, enables many proteins to act as [[enzymes]], catalyzing a wide range of specific biochemical transformations within cells. In addition, proteins have evolved the ability to bind a wide range of [[Cofactor (biochemistry)|cofactors]] and [[coenzymes]], smaller molecules that can endow the protein with specific activities beyond those associated with the polypeptide chain alone.