- CAS
- 367-93-1
- Form
- Powder
- Ask
- Dioxane residue and whether the lot was sterile filtered
IPTG induces lac-controlled expression. Dioxane is a process residue that protein work often limits, so it belongs on the inquiry.
What it is
IPTG (isopropyl β-D-1-thiogalactopyranoside) is a synthetic analog of allolactose. It binds the lac repressor (LacI) and releases it from the operator, switching on lac-controlled genes. Because the thioglycoside bond is not hydrolyzed by β-galactosidase, the inducer concentration stays constant during culture.
Where it is used
- Recombinant protein expression from T7lac, tac and trc promoters in E. coli, typically 0.1–1 mM final.
- Low-temperature induction (about 16–25 °C) with lower IPTG, often 0.1–0.5 mM, to improve solubility.
- Blue-white colony screening together with X-gal, commonly around 0.1–0.5 mM in plates.
- Lac-inducible reporter and regulatory studies. Selection antibiotics are on antibiotics and expression.
Handling tips
- Prepare a 0.1–1 M stock in water, filter-sterilize (0.22 µm), aliquot and store at −20 °C.
- The powder is hygroscopic; keep it sealed, dry and cool.
- Optimize concentration and induction time per construct; more IPTG does not always mean more soluble protein.
What to specify when ordering
- Purity and dioxane residue limit.
- Powder, or sterile solution with the concentration.
- Pack size.
Properties and storage
- Formula
- C9H18O5S
- Molecular weight
- 238.30
- Appearance
- White crystalline powder
- Solubility
- Freely soluble in water (stocks usually 0.1–1 M)
- Storage
- Powder 2–8 °C or −20 °C, dry; stock aliquoted at −20 °C
- Typical packs
- 1 g, 5 g, 25 g, 100 g
Typical literature values. The batch COA / SDS governs.
Before you inquire
Is a sterile IPTG solution available?
Powder and sterile solution can both be inquired. For a solution, give the concentration.
Why does dioxane residue matter?
Dioxane can remain from manufacture. It is a solvent of toxicological concern, so protein and IVD users often set a limit on it.
What is the molecular weight of IPTG?
About 238.3 g/mol, so 1 M is roughly 2.38 g in 10 mL of water.
Does IPTG work without a lac system?
No. It acts only through the lac repressor, so the vector or host must carry lacI and a lac-operator promoter.
Pack sizes and catalogue numbers
CTH10018-100G
Prices on request; lead time confirmed on the quotation.
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Send an inquiryFor research or industrial use only. Not for human or animal diagnosis or treatment, and not for drug or food use. Grade, pack size and lead time follow the supplier batch COA / SDS. Figures on this site are general industry references, not a factory specification.