Title: IPTG
CAS Registry Number: 367-93-1
CAS Name: 1-Methylethyl 1-thio-b-D-galactopyranoside
Synonyms: isopropyl b-D-thiogalactopyranoside
Molecular Formula: C9H18O5S
Molecular Weight: 238.30
Percent Composition: C 45.36%, H 7.61%, O 33.57%, S 13.46%
Literature References: Artificial, slow-hydrolyzing inducer of the lactose (
lac) operon. Prepn: B. Helferich, D. Türk,
Ber. 89, 2215 (1956); U. Carlsson
et al., Protein Eng. 4, 1019 (1991). Induction of b-galactosidase: V. Paces
et al., Collect. Czech. Chem. Commun. 38, 2983 (1973). Binding to b-D-galactosidase: C. K. De Bruyne, M. Yde,
Carbohydr. Res. 56, 153 (1977). Concentration effects on
lac operon induction in
E. coli: S. Cho
et al., Biochem. Biophys. Res. Commun. 128, 1268 (1985). Effect of lactose permease on induction by IPTG: L. H. Hansen
et al., Curr. Microbiol. 36, 341 (1998).
Properties: mp 109.5-110.5°. [a]D22 -31.4° (c = 5 in water). Also reported as crystals from dioxane, mp 118-119°. [a]D -26.4° (c = 1 in water) (Carlsson). Log P (octanol/water): -1.26.
Melting point: mp 109.5-110.5°; mp 118-119°
Optical Rotation: [a]D22 -31.4° (c = 5 in water); [a]D -26.4° (c = 1 in water) (Carlsson)
Log P: Log P (octanol/water): -1.26
Use: Induces protein synthesis in
E. coli when transcription is controlled by the
lac-promoter. In conjunction with X-gal,
q.v., in detection of
lac gene activity during cloning experiments.
