sirtuin
n.— «Sirtuins are a recently discovered family of enzymes that promote normal cellular function. In particular, sirtuins improve the function of mitochondria which generate energy in cells. When organisms face adversity, sirtuins are activated as part of a natural process that maintains healthy function.» —“Sirtris Pharmaceuticals to Present at BIO Investor Forum, October 19th, 2006″ in Cambridge, Massachusetts BusinessWire Oct. 17, 2006. (source: Double-Tongued Dictionary)