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In computational biology, protein pK a calculations are used to estimate the pK a values of amino acids as they exist within proteins.These calculations complement the pK a values reported for amino acids in their free state, and are used frequently within the fields of molecular modeling, structural bioinformatics, and computational biology.
The value of pK a also depends on molecular structure of the acid in many ways. For example, Pauling proposed two rules: one for successive pK a of polyprotic acids (see Polyprotic acids below), and one to estimate the pK a of oxyacids based on the number of =O and −OH groups (see Factors that affect pK a values below).
For example, the acid may be acetic acid and the salt may be sodium acetate. The Henderson–Hasselbalch equation relates the pH of a solution containing a mixture of the two components to the acid dissociation constant, K a of the acid, and the concentrations of the species in solution. [6]
The pyrophosphate anion has the structure P 2 O 4− 7, and is an acid anhydride of phosphate. It is unstable in aqueous solution and hydrolyzes into inorganic phosphate: P 2 O 4− 7 + H 2 O → 2 HPO 2− 4. or in biologists' shorthand notation: PP i + H 2 O → 2 P i + 2 H +
Oxalate (systematic IUPAC name: ethanedioate) is an anion with the chemical formula C 2 O 2− 4.This dianion is colorless. It occurs naturally, including in some foods. It forms a variety of salts, for example sodium oxalate (Na 2 C 2 O 4), and several esters such as dimethyl oxalate ((CH 3) 2 C 2 O 4).
A buffer solution is a solution where the pH does not change significantly on dilution or if an acid or base is added at constant temperature. [1] Its pH changes very little when a small amount of strong acid or base is added to it.
Examples for such compounds are NTMP, EDTMP and DTPMP. These phosphonates are the structural analogues to the well-known aminopolycarboxylate such as EDTA. The stability of the metal complexes increases with increasing number of phosphonic acid groups. Phosphonates are highly water-soluble while the phosphonic acids are only sparingly so.
For example, acetic acid is a weak acid which has a = 1.75 x 10 −5. Its conjugate base is the acetate ion with K b = 10 −14 / K a = 5.7 x 10 −10 (from the relationship K a × K b = 10 −14 ), which certainly does not correspond to a strong base.