What are the units for extinction coefficient?
The extinction coefficient is the absorbance divided by the concentration and the pathlength, according to Beer’s Law (epsilon = absorbance/concentration/pathlength). The units of extinction coefficients are usually M-1cm-1, but for proteins it is often more convenient to use (mg/ml)-1cm-1.
What is the extinction coefficient of pNP at 405 nm?
The p-nitrophenol from substrate hydrolysis was measured at 405 nm using a spectrophotometer. The molar extinction coefficient of the p-nitrophenol in this buffer system was 1,725 M−1 cm−1.
What is the extinction coefficient of pNP at 400 nm?
21,000 M-l-cm -1
The molar extinction coefficient of p-nitrophenol measured at 400 nm was 21,000 M-l-cm -1.
What is the pKa of 4-Nitrophenol?
Structure for HMDB0001232 (4-Nitrophenol)
| Property | Value | Source |
|---|---|---|
| pKa (Strongest Acidic) | 7.07 | ChemAxon |
| pKa (Strongest Basic) | -7.1 | ChemAxon |
| Physiological Charge | 0 | ChemAxon |
| Hydrogen Acceptor Count | 3 | ChemAxon |
What is absorption coefficient units?
The absorption coefficient is essentially the cross-sectional area per unit volume of medium. Experimentally, the units [cm-1] for µa are inverse length, such that the product µaL is dimensionless, where L [cm] is a photon’s pathlength of travel through the medium.
What is the role of p-nitrophenol pNP in the enzyme assay?
p-Nitrophenyl Phosphate (PNPP) is a non-proteinaceous, non-specific substrate used to assay protein, alkaline and acid phosphatases. The assay can be used for the quick analysis of the protein phosphatase activity under any non-standard conditions.
What is the extinction coefficient of p-nitrophenol?
The extinction coefficient (ε) of p-nitrophenol was determined to be 15,000 M−1cm−1 under the assay conditions.
What is the extinction coefficient of pNP?
The absorbance was converted to a concentration scale by a molar extinction coefficient of 12,800 M-1 cm-1 for 4-nitrophenol (pNP).
What is the extinction coefficient of alkaline phosphatase?
Optimum pH: 8.0 (Garen and Levinthal 1960). Extinction coefficient: E278 = 7.2 (Anderson et al. 1975). Isoelectric point: pH 4.5 (Garen and Levinthal 1960).
Why is pNP yellow?
A lone pair from the oxygen can be delocalized via conjugation to the benzene ring and nitro group. Since the length of conjugated systems affects the color of organic compounds, this ionization change causes the 4-nitrophenol to turn yellow when fully deprotonated and existing as 4-nitrophenolate.
How is the amount of 4-nitrophenol measured?
Amounts of 4-nitrophenol produced by a particular enzyme in the presence of its corresponding substrate can be measured with a spectrophotometer at or around 405 nm and used as a proxy measurement for the amount of the enzyme activity in the sample.
Are there any known carcinogenic effects of 4-nitrophenol?
No information is available on the reproductive, developmental, or carcinogenic effects of 4-nitrophenol in humans. EPA has not classified 4-nitrophenol for potential carcinogenicity. 4-nitrophenol
What is the role of 4-nitrophenol in xenobiotics?
p-Nitrophenol. 4-nitrophenol is a member of the class of 4-nitrophenols that is phenol in which the hydrogen that is para to the hydroxy group has been replaced by a nitro group. It has a role as a human xenobiotic metabolite and a mouse metabolite. It is a conjugate acid of a 4-nitrophenolate.
What is the dissociation constant of 4-nitrophenol?
In solution, 4-nitrophenol has a dissociation constant (pK a) of 7.15 at 25 °C. 4-Nitrophenol can be used as a pH indicator.
