O-Nitrophenyl P-D-galactopyranosid

AA AAm Con A DSS DSS-gel LCST MAPTAC MBA MP MP-gel NIPA ONPG PVMA SSPG Tc TMED acrylic acid acrylamide concanavalin A dextran sulfate sodium gel containing Con A/DSS complex lower critical solution temperature [(methacrylamide)propyl]trimethylammonium chloride /V,/V -methylenebis(acrylamide) a-methyl-D-mannopyranoside gel containing Con A/MP complex /V-isopropylacrylamide O-nitrophenyl-P-D-galactopyranoside poly(vinyl methyl ether) stimulus-sensitive polymer gel transition temperature /V,/V,/V, /V -tetramethylethylenediamine... 

If the ELISA color development takes more than a few minutes, continue the incubation in the dark. P-galactosidase reactions tend to have a lower spontaneous background than peroxidase reactions but the yellow o-nitrophenyl-P-D-galactopyranoside reaction product can take longer to develop, p-galactosidase reactions can be speeded up by incubation at 37°C. 

Substrate solution for -galactosidase 4 mg/mL O-nitrophenyl-p-D-galactopyranoside (ONPG) dissolved in TBS containing 0.7% 2-mercaptoethanol and 1 mMMgClg. 

The method is proposed to be applicable to solutions of lactase between 2000 and 5000 units/g, where one enzymatic unit is defined as the quantity of enzyme that liberates 1.30 pmol o-nitrophenol/min under assay conditions. Lactase decomposes the artificial substrate o-nitrophenyl-p-D-galactopyranoside into o-nitrophenol and galactose. Absorbance of o-nitrophenol (yellow in alkaline medium) is measured to estimate the enzymatic activity, at 420 nm. 

The reagent is prepared by the addition of a solution containing 70 mg of o-nitrophenyl-P-D-galactopyranoside (ONPG) per 100 mL of 0.1 AT potassium phosphate buffer, pH 7.0, containing 1 mM magnesium chloride and 0.01 AT2-mercaptoethanol. The reaction may be stopped by the addition of 0.25 vol of 2 AT sodium carbonate. 

Mori and Okahata (1998) Batch Transgalactosylation from 1-O-p-nitrophenyl-P- D-galactopyranoside to 5-phenylpentan-l-ol P- D-galactosidase... 

Kinetic spectrophotometric assays for Na are based on activation of the enzyme p-galactosidase by Na" to hydrolyze o-nitrophenyl-[3-D-galactopyranoside (ONPG). The rate of production of o-nitrophenol (the chromophore) is measured at 420 nm. 

S-Galactosidase from E. coli (Sigma Chemical Co.) (50 U) no reported risk (1 U will hydrolyse 1.0 p,mol of o-nitrophenyl- 3-D-galactopyranoside to o-nitrophenol and galactose per minute at pH 7.3 and 37 °C)... 

Phenyl and p-nitrophenyl /3-D-galactopyranoside, as well as lactose, were poorly inhibitory.19,478 The high lectin-reactivity reported for 2 -O-L-fucosyllactose is interesting, but inconsistent with the observed carbohydrate-binding specificity of the lectin (the authors might well have tested the very active trisaccharide just noted).196... 

Methyl a-D-galactopyranoside, melibiose, p-nitrophenyl a-D-galactopyranoside, 2-O-a-D-galactopyranosyl-D-glu-cose, O-a-D-galactopyranosyl-myo-inositol 0.62... 

For each type of assay, the label or tag involved is listed along with typical substrates, type of absorbance, and type of instrument required. RIA radioimmunoassay IRMA immunoradiometric assay CPM counts per minute ELISA enzyme linked immunosorbent assay EIA enzyme immunoassay TMB 5,5 tetramethylbenzidine HPA p hydroxyphenylacetic acid AMPPD 4 methoxy 4 (3 phosphatephenyl) spiro(l,2 dioxetane) 3,2 adamantane p NPP p nitrophenyl phosphate 4 MUP 4 methylumbelliferyl phosphate ONPG o nitrophenyl P galactopyranoside MUG 4 methylumbelliferyl P D galactopyrano side AMPGD 3 (4 methoxyspiro( 1,2 dioxetane 3,2 tricyclo(3.3.1.1(3,7))decan) 4 yl)phenylgalacto pyranoside ECL electrochemiluminescence. 

To complete the evaluation of the relative reactivities of disarmed-latent p-nitrophenyl thioglycosyl acceptors, glycosidation of p-nitrophenyl 2,3,4-tri-O-benzyl-l-thio-p-D-galactopyranoside 46 was examined using the acceptor 17. Consumption of acceptor 17 took place within 1 h and, similar to its reaction with 47, an anomeric mixture of disaccharide 48 was isolated (76% yield) as a 4 1 mixture of the a/p-anomers due to the nonparticipating effect of 2-O-benzyl ether. 

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