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| | 2-Nitrophenyl-beta-D-galactopyranoside Basic information |
| | 2-Nitrophenyl-beta-D-galactopyranoside Chemical Properties |
| Melting point | 186-193 °C (dec.) | | alpha | -70 º (c=1, H2O) | | Boiling point | 442.39°C (rough estimate) | | density | 1.3709 (rough estimate) | | refractive index | -68.8 ° (C=1, H2O) | | storage temp. | 2-8°C | | solubility | DMSO (Slightly), Water (Slightly, Heated, Sonicated) | | pka | 12.69±0.70(Predicted) | | form | Powder | | color | White to very slightly yellow | | optical activity | [α]20/D 70±1°, c = 1% in H2O | | Water Solubility | Soluble in water. | | BRN | 92207 | | InChIKey | KUWPCJHYPSUOFW-RMPHRYRLSA-N | | CAS DataBase Reference | 369-07-3(CAS DataBase Reference) | | NIST Chemistry Reference | Galactopyranoside, o-nitrophenyl, beta-d-(369-07-3) |
| | 2-Nitrophenyl-beta-D-galactopyranoside Usage And Synthesis |
| Description | 2-Nitrophenyl-β-D-galactopyranoside (ONPG) is a colorimetric and spectrophotometric substrate for detecting β-galactosidase activity. This compound is usually colorless. However, if β-galactosidase is present, it hydrolyzes the ONPG molecule into galactose and ortho-nitrophenol. The latter compound has a yellow color that can be used to check for enzyme activity utilizing a colorimetric assay (at 420 nm wavelength). β-Galactosidase is required for lactose utilization, so the intensity of the color produced can be used to measure the enzymatic rate. Though ONPG mimics lactose and is hydrolyzed by β-galactosidase, it cannot act as an inducer for the lac operon. Without another lactose analog that can act as an inducer, such as isopropyl β-D-1-thiogalactopyranoside (IPTG), β-galactosidase will not be transcribed and ONPG will not be hydrolyzed. | | Chemical Properties | White Crystalline Solid | | Uses | 2-Nitrophenyl-beta-D-galactopyranoside is a β-Galactosidase substrate for colorimetric and EIA applications; counterpart of widely employed pNPP/alkaline phosphatase substrate. | | Definition | ChEBI: A beta-D-galactoside having a 2-nitrophenyl substituent at the anomeric position. | | General Description | ONPG (2-Nitrophenyl β-D-galactopyranoside) is a colorimetric substrate for β-galactosidase. | | Biochem/physiol Actions | β-galactosidase, breaks down lactose into galactose and glucose. β-Galactosidase is not lactose specific and can act on simple galactosides. 2-Nitrophenyl β-D-galactopyranoside hydrolysis results in the release of galactose and a yellow chromogenic compound. The test substrate does not depend on an induced or constitutive permease enzyme to enter the cell, therefore reactions are rapid and occur within a 24-hour period. | | Purification Methods | Purify 2-nitrophenyl--D-galactopyranoside by recrystallisation from EtOH. [Seidman & Link J Am Chem Soc 72 4324 1950, Snyder & Link J Am Chem Soc 75 1758 1953]. It is a
chromogenic substrate for -galactosidases [Jagota et al. J Food Sci 46 161 1981]. [Beilstein 17/7 V 52.] |
| | 2-Nitrophenyl-beta-D-galactopyranoside Preparation Products And Raw materials |
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