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Ascorbic acid is an organic compound with formula C 6 H 8 O 6, ... The ascorbate ion is the predominant species at typical biological pH values.
Nitric acid, with a pK value of around −1.7, behaves as a strong acid in aqueous solutions with a pH greater than 1. [23] At lower pH values it behaves as a weak acid. pK a values for strong acids have been estimated by theoretical means. [24] For example, the pK a value of aqueous HCl has been estimated as −9.3.
Ascorbic acid is a weak sugar acid structurally related to glucose. In biological systems, ascorbic acid can be found only at low pH, but in solutions above pH 5 is predominantly found in the ionized form, ascorbate. [8] Many analytical methods have been developed for ascorbic acid detection.
Dehydroascorbic acid (DHA) is an oxidized form of ascorbic acid (vitamin C). It is actively imported into the endoplasmic reticulum of cells via glucose transporters. [ 1 ] It is trapped therein by reduction back to ascorbic acid by glutathione and other thiols . [ 2 ]
An example of a mineral ascorbate drug is sodium ascorbate injections (the acid form, ascorbic acid, of vitamin c is too acidic for injections). Ascorbate salts may be better tolerated by the human body than the corresponding weakly acidic ascorbic acid. Ascorbates are highly reactive antioxidants used as food preservatives. [2]
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 ...
[1] [2] If vitamin C, which is a good reducing agent, is present, the blue dye, which turns pink in acid conditions, is reduced to a colorless compound by ascorbic acid. This reaction is a redox reaction: vitamin C (ascorbic acid) is oxidized to dehydroascorbic acid , and DCPIP is reduced to the colorless compound DCPIPH 2
As the sodium salt of ascorbic acid, it is known as a mineral ascorbate. It has not been demonstrated to be more bioavailable than any other form of vitamin C supplement. [2] Sodium ascorbate normally provides 131 mg of sodium per 1,000 mg of ascorbic acid (1,000 mg of sodium ascorbate contains 889 mg of ascorbic acid and 111 mg of sodium).