- One of the major components that makes up natural rubber and is used to make synthetic rubbers. It is also emitted from plants and trees, has been detected in tobacco smoke and automobile exhaust. Isoprene is a possible carcinogen (cancer-causing agent). The US government in 2000 classified it as "reasonably anticipated to be a human carcinogen." In laboratory animal studies of isoprene, cancer was observed in multiple organ sites following long-term inhalation exposures.
* * *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.
* * *iso·prene 'ī-sə-.prēn n a flammable liquid unsaturated hydrocarbon C5H8 used esp. in synthetic rubber
* * *iso·prene (iґso-prēn) an unsaturated branched chain five-carbon hydrocarbon that is the molecular unit of isoprenoid compounds.
Medical dictionary. 2011.