2-Methyl-1,3-butadiene; an unsaturated five-carbon hydrocarbon with a branched chain, which in the plant and animal kingdom is used as the basis for the formation of isoprenoids, e.g., terpenes, carotenoids and related pigments, rubber. Fat-soluble vitamins either are isoprenoid or have isoprenoid side chains; steroids are synthesized via isoprenoid intermediates, as are ubiquinone, dolichol, and prenylated proteins.
