IPTG (Isopropyl D-thiogalactopyranoside) .

Description:

IPTG is a highly stable synthetic analog of lactose. It inactivates the lac repressor and induces synthesis of beta-galactosidase. The IPTG is used to induce the expression of cloned genes which are under control of the lac operon. It is used in conjunction with X-Gal to determine the lac phenotype in blue/white colony screening.