X-Gal-1g

-X-Gal, Ultra Pure Grade

-X-Gal (5-Bromo-4-Chloro-3-indolyl-β-D-galactopyranoside) is a chromogenic substrate for β-galactosidase used in conjunction with IPTG to idenify bacterial colonies that contain recombinant plasmids by blue/white selection. X-Gal forms an intense blue precipitate in the presence of β-galactosidase activity. In experiments using vector containing the lacZ gene, recobinant colonies(white) can be identified quite ready from bacterial colonies that contain non-recombinant plasmids (blue).