Isopropyl-ß-D-thiogalactopyranoside (IPTG)

Product ID: I373

Introduction

Description: IPTG is a lactose-mimic which binds to the lac repressor to enhance expression of the lac Z gene
Synonym: Isopropyl-ß-D-Thiogalactopyranoside

I373 Isopropyl-β-Dthiogalactopyranoside

Application Notes
Isopropyl-β-D-thiogalactopyranoside is often referred as IPTG. It acts as a substrate for β- glactosidase by inducing the expression of lac operon in Escherichia coli. IPTG binds to the repressor and modifies its form which then prevents the repression of lac gene coding by β- glactosidase. Additionally, IPTG is also a substrate and inducer for thiogalactoside transacetylase and penicillinase activity in bacteria, respectively

IPTG is often used in cloning procedures where induction of β-glactosidase activity is required. It is also widely used along side of X-Gal (Prod. No. X874) for blue-white colony screening of recombinant bacteria.

Blue/White Colony Screening:
1. Dissolve X-Gal (Prod. No. X874) in DMF (dimethylformamide) or DMSO (dimethyl sulfoxide) (Prod. No. D241) to make a 20 mg/ml solution. Wrap in aluminum foil to protect from light.
2. Prepare IPTG (Prod. No. I373) by dissolving 2 g in 8 ml of H2O, then adjust level to 10 ml and filter sterilize using a 0.22-micron filter. Dispense into 1mL aliquots.
3. Store both solutions at -20о C. Avoid freeze/thaw cycles as this can cause false results.
4. For use, spread 40 μL of stock X-Gal and 4 μL of IPTG onto surface of pre-made LB (prepared using LB Agar, Prod. No. L465) plate.