isopropyl-beta-D-thiogalactopyranoside /ˌaɪsəˈproʊpəl ˈbeɪtə ˈdiː wʌn ˌθaɪoʊɡəˌlæktoʊpaɪˈrænəsaɪd/ noun1 •A synthetic chemical used to turn on gene expression by activating the lac operon, Commonly used in molecular biology to induce the production of recombinant proteins.
