Search results
Results from the WOW.Com Content Network
The experimental determination of pK a values is commonly performed by means of titrations, in a medium of high ionic strength and at constant temperature. [58] A typical procedure would be as follows. A solution of the compound in the medium is acidified with a strong acid to the point where the compound is fully protonated.
See Amino acid for the pK a values of all amino acid side chains inferred in such a way. There are also numerous experimental studies that have yielded such values, for example by use of NMR spectroscopy. The table below lists the model pK a values that are often used in a protein pK a calculation, and contains a third column based on protein ...
Any acid with a value which is less than about -2 behaves as a strong acid. This results from the very high buffer capacity of solutions with a pH value of 1 or less and is known as the leveling effect. [3] The following are strong acids in aqueous and dimethyl sulfoxide solution.
In the case of multiple pK values they are designated by indices: pK 1, pK 2, pK 3 and so on. For amino acids, the pK 1 constant refers to its carboxyl (–COOH) group, pK 2 refers to its amino (–NH 2) group and the pK 3 is the pK value of its side chain.
In cell biology, ion trapping is the build-up of a higher concentration of a chemical across a cell membrane due to the pKa value of the chemical and difference of pH across the cell membrane. [1] [2] This results in basic chemicals accumulating in acidic bodily fluids such as the cytosol, and acidic chemicals accumulating in basic fluids.
Polyacids accept protons at low pH values. At higher pH values, they deprotonate and become negatively charged. [1] The negative charges create a repulsion that causes the polymer to swell. This swelling behavior is observed when the pH is greater than the pKa of the polymer. [2]
These values below are pK a values determined in dimethylsulfoxide (DMSO), which has a broader useful range (~0 to ~35) than values determined in water (~0 to ~14) and better reflect the basicity of the carbanions in typical organic solvents. Values below less than 0 or greater than 35 are indirectly estimated; hence, the numerical accuracy of ...
A smaller H + concentration means a greater OH − concentration and, therefore, a greater K b and a greater pH. NaOH (s) (sodium hydroxide) is a stronger base than (CH 3 CH 2) 2 NH (l) (diethylamine) which is a stronger base than NH 3 (g) (ammonia). As the bases get weaker, the smaller the K b values become. [1]