Ascorbic add

In ketones existing largely as the enol, palladium may prove effective in minimizing hydrogenolysis, Hydrogen was added slereoselectively to the least hindered side of L-ascorbic add (3) to give L-gulono-1,4-lactone (4)... 

Ascorbic acid, HQHt06, also known as vitamin C, is a weak acid. It is an essential vitamin and an antioxidant. A solution of ascorbic add is prepared by dissolving 2.00 g in enough water to make 100.0 mL of solution. The resulting solution has a pH of 2.54. What is Ka for ascorbic acid ... 

Ascorbic add (hRf 50-55) appeared as a brown-red chromatogram zone that was only stable for ca. 20 min the background was yellow. The detection limit was less than 100 ng substance per chromatogram zone. 

Bromophenol blue (3.0...4.6) aliphatic carboxylic acids [225 —228] malonic and lactic adds [229] palmitic and lactic acids [230] malonic, glycolic, malic, dtric, tartaric, ketoglutaric, galacturonic and oxalic adds [196] dicarboxylic acids, sucdnic acid [231] indoleacetic add, trichloroacetic acid [232] palmitic acid, palmityl- and stearyllactic add [223] benzoic, sorbic and salicylic acid [234] metabolites of ascorbic add [235] chloropropionic add [236] oligogalacturonic adds [237] amino adds, hydrocarbons, mono-, di- and triglycerides [238] xylobiose, xylose, glucose and derivatives [239] sugar alcohols [91] toxaphene [240]... 

The following reactions are to be expected with ascorbic add and dehydroascorbic... 

Reddish or bluish chromatogram zones [3, 9 are produced, amino sugars and amino adds also react. Unexpectedly ascorbic add also reacts. 

Another function of ascorbic add is to generate Fe(II) from Fe (III), which is part of the Haber-Weiss-Fenton Reaction (77). In that reaction, peroxide is reduced to the hydroxyl radical, HO, an extremely powerful oxidizing agent. It should also be noted that ascorbic acid can chelate metals 18 and will promote the carbohydrate-amine browning reaction (79-20). 

A number of inhibitors of carcinogen- and radiation-induced ceU transformation have been identified. These include protease inhibitors (antipain, leupeptin, soybean tryspin inhibitor), vitamin A analogs (retinoids), vitamin C (ascorbic add), glucocorticoids, and lymphotoxins (Kennedy, 1984). 

Number of Years Number of Varieties Ascorbic Add Content in mg/100 grams ... 

With ascorbic add, silver was reduced to metallic silver although at room temperature the reaction was slow enough for a measurement of the instability constant (A = 2.2 0.2 x 10 4 hence log j8i = 3.66 0.04).265... 

Whilst these acids are of minor importance in man, another multifunctional acid, ascorbic add (vitamin C 6), has an apparent role in human iron metabolism as one of the postulated factors aiding iron uptake. Ascorbic add reduces Fe111 to Fe" with probable complexation of the latter. It thus converts Fe"1 to a more soluble form. Ascorbic acid can also reduce Cu" to Cu1 (equation 1), and there is accumulating evidence of a link between the metabolism of ascorbic acid and that of Cu.34... 

Two-Step Fermentation Process to 2-Ketogulonic Acid with Chemical Step to Ascorbic Add... 

G. C. Andrews, 5,6-Anhydro-L-ascorbic add. A reactive intermediate for the formation of 6-substituted derivatives of L-ascorbic acid, Carboydr. Res., 134 (1984) 321-326. 

Rather surprisingly, the average person knows the names of several cofactors and coenzyme precursors, because many of these cannot be synthesized in vivo, and must be supplied in one s diet. This is the reason why a balanced diet should include retinol (vitamin A), ascorbic add (vitamin C), tocopherol (vitamin E), thiamine (vitamin Eh), folic acid etc., as well as zinc and iron. 

Tamogami, S., Rakwal, R., Kodama, O. Phytoalexin production elidted by exogenously applied jasmonic add in rice leaves (Oryza sativa L.) is under the control of cytokinins and ascorbic add. FEBS Lett 1997b 412 61-64. 

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