Search results
Results From The WOW.Com Content Network
The complete data for Tryptophan ... Molar mass: 204.23 g·mol −1 Systematic name: (S)-2-Amino-3-(1H-indol-3-yl)-propanoic acid Abbreviations: W, Trp Synonyms:
This reaction is rapid and stoichiometric, with the addition of one mole of thiol releasing one mole of TNB. The TNB 2− is quantified in a spectrophotometer by measuring the absorbance of visible light at 412 nm, using an extinction coefficient of 14,150 M −1 cm −1 for dilute buffer solutions, [4] [5] and a coefficient of 13,700 M −1 cm −1 for high salt concentrations, such as 6 M ...
In biochemistry, the molar absorption coefficient of a protein at 280 nm depends almost exclusively on the number of aromatic residues, particularly tryptophan, and can be predicted from the sequence of amino acids. [6] Similarly, the molar absorption coefficient of nucleic acids at 260 nm can be predicted given the nucleotide sequence.
This characteristic is used in quantitative analysis, notably in determining the concentrations of these amino acids in solution. [1] [2] Most proteins absorb at 280 nm due to the presence of tyrosine and tryptophan. Of the aromatic amino acids, tryptophan has the highest
It is done in one step where the Bradford reagent is added to a test tube along with the sample. After mixing well, the mixture almost immediately changes to a blue color. When the dye binds to the proteins through a process that takes about 2 minutes, a change in the absorption maximum of the dye from 465 nm to 595 nm in acidic solutions ...
Extinction coefficient refers to several different measures of the absorption of light in a medium: Attenuation coefficient , sometimes called "extinction coefficient" in meteorology or climatology Mass extinction coefficient , how strongly a substance absorbs light at a given wavelength, per mass density
absorption coefficient is essentially (but not quite always) synonymous with attenuation coefficient; see attenuation coefficient for details; molar absorption coefficient or molar extinction coefficient , also called molar absorptivity , is the attenuation coefficient divided by molarity (and usually multiplied by ln(10), i.e., decadic); see ...
The Beer–Lambert law can be applied to the analysis of a mixture by spectrophotometry, without the need for extensive pre-processing of the sample. An example is the determination of bilirubin in blood plasma samples. The spectrum of pure bilirubin is known, so the molar attenuation coefficient ε is known.