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Key Documents

N1127

Sigma-Aldrich

2-Nitrophenyl β-D-galactopyranoside

≥98% (enzymatic)

Synonym(s):

ONPG , o-Nitrophenyl β-D-galactopyranoside, ONPG

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About This Item

Empirical Formula (Hill Notation):
C12H15NO8
CAS Number:
Molecular Weight:
301.25
Beilstein:
92207
EC Number:
MDL number:
UNSPSC Code:
12352200
PubChem Substance ID:
NACRES:
NA.52

grade

for molecular biology

Assay

≥98% (enzymatic)

form

powder

storage temp.

−20°C

SMILES string

OC[C@H]1O[C@@H](Oc2ccccc2[N+]([O-])=O)[C@H](O)[C@@H](O)[C@H]1O

InChI

1S/C12H15NO8/c14-5-8-9(15)10(16)11(17)12(21-8)20-7-4-2-1-3-6(7)13(18)19/h1-4,8-12,14-17H,5H2/t8-,9+,10+,11-,12-/m1/s1

InChI key

KUWPCJHYPSUOFW-YBXAARCKSA-N

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General description

ONPG (2-Nitrophenyl β-D-galactopyranoside) is a colorimetric substrate for β-galactosidase.

Application

2-Nitrophenyl β-D-galactopyranoside is an enzyme substrate used to detect lacZ activity and hence the presence of 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.

Principle

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.

Reconstitution

A stock solution can be prepared in molecular biology grade water at a concentration of 3 mg/ml. Alternatively, a stock solution of approximately 20.5 mg/ml is prepared in 100 mM sodium phosphate buffer (pH 7.3). Gentle warming may be required to completely dissolve the product.

Substrates

Chromogenic substrate for β-galactosidase

Storage Class Code

11 - Combustible Solids

WGK

WGK 3

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

Certificates of Analysis (COA)

Search for Certificates of Analysis (COA) by entering the products Lot/Batch Number. Lot and Batch Numbers can be found on a product’s label following the words ‘Lot’ or ‘Batch’.

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D R Henderson et al.
Clinical chemistry, 32(9), 1637-1641 (1986-09-01)
Genetic engineering of beta-galactosidase (EC 3.2.1.23) has led to the development of a new homogeneous assay system, CEDIA. The Z gene of the lac operon of Escherichia coli encodes a large enzymatically inactive polypeptide that spontaneously aggregates and folds to
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