Pyruvate structural formula

Outline in detail, using structural formulas, the enzyme-catalyzed reactions by which cells in the human body convert glyceraldehyde 3-phosphate into pyruvate. 

Figure 5.4 Structural formulae of thiamin phosphate esters. At present, five natural thiamin phosphate derivatives have been described thiamin monophosphate (ThMP) thiamin diphopshate (ThDP) thiamin triphosphate (ThTP) adenosine thiamin diphosphate (AThDP) and adenosine thiamin triphosphate (AThTP). Catalytic intermediates, such as for instance a-hydroxyethyl thiamine diphosphate formed by the action of yeast pyruvate decarboxylase (EC 4.1.1.1), are not considered here.

Exercise 17.3, on the previous page, mentions that pyruvic acid is formed in biological cells. In muscle tissue, glucose is broken down to pyruvic acid, which is eventually oxidized to carbon dioxide and water. The structural formula of pyruvic acid is... 

The structure of cocarboxylase (see Fig. 1 for formula) was established by Lohmann and Schuster. A long-established function of cocarboxylase (thiamine pyrophosphate, aneurin) is as the coenzyme of a-ketoaeid carboxylase. Mg++ is also required. The reaction involved is the nonoxidative decarboxylation of an a-keto acid to CO2 and an aldehyde with one less carbon atom. The most important example is the splitting of pyruvic acid to acetaldehyde and CO2 (equation 9). This... 

Xanthan gum can be regarded as a cellulose derivative. The main chain consists of 1,4 linked P-glucopyranose residues. On an average, every second glucose residue bears in the 3-position a trisaccharide of the structure P-D-Man/ -(1 4)-P-d-G1c/ A(1 2)-a-D-Man/7 as the side chain. The mannose bound to the main chain is acetylated in position 6 and ca. 50% of the terminal mannose residues occur ketahzed with pyruvate as 4,6-0-(l-carboxyethylidene)-D-mannopyranose (cf. Formula 4.162 GlcpA glucuronic acid). 

Thiamine Vitamin Bi) is one of the longest-known vitamins. Its chemical structure is somewhat complicated it contains two heterocyclic rings (a pyrimidine and a thiazol ring, formula in Chapt. VI-5) connected at a quaternary N atom. It can easily be converted to the dihydro form, but its catalytic function does not seem to be that of a redox sy.stem. Thiamine pyrophosphate is the coenzyme of decarboxylases and aldehyde transferases. It plays a key role in oxidative decarboxylation of pyruvate (in the breakdown of carbohydrate) and of a-keto glutarate (in the citrate cycle). Man s requirements of thiamine are calculated in conjunction with his caloric intake, since the demand for the coenzyme is apparently higher wth a high overall metabolic rate. 

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