2,3-Phosphoglyceric acid

Dehydration of Phosphoolyceric Acid The enolase reaction whereby water is removed  

---

The net result of photosynthesis is reduction of carbon dioxide to form carbohydrates. A key intermediate is phosphoglyceric acid, from which various simple sugars are produced and disproportionated to form other carbohydrates. 

A. Phosphoenolpyruvate.—The mechanisms of hydrolysis of phosphate esters of phosphoenol pyruvic acid (33) have been described in detail, and 0 studies confirm an earlier postulate that attack by water on the cyclic acyl phosphate (34) occurs at phosphorus and not at carbon. In the enolase reaction, the reversible interconversion of 2-phosphoglyceric acid(35)... 

The simultaneous determination of dissolved organic carbon and phosphorus is feasible [39]. Phosphoglyceric acid (1 g equivalent P) was added to membrane-filtered, pre-irradiated seawater, and the phosphate was measured before and after ultraviolet irradiation using an autoanalyser. The recovery of organic phosphorus was 100%. 

Phosphorus was determined in the extracts by the spectrophotometric method of Murphy and Riley [63] and Stickland and Parsons [96]. In Table 12.10 results are shown obtained upon applying the procedure to the determination of total phosphorus in solutions of calcium phosphoglyceric acid. 

Table 12.10 Results of analysis of phosphoglyceric acid solutions...

This aldehyde undergoes dismutation to glycerophosphoric add and phosphoglyceric acid (half and half) ... 

Light was required for the generation of NADPH needed to reduce phosphoglyceric acid to give glyceraldehyde 3-phosphate. The NADPH was then used to give the three molecules of ATP needed to phospho-rylate ribulose phosphate and the triose phosphates, so completing the Calvin cycle. 

G.M. Blackburn, D.L. Jakemean, A.J. Ivory, M.P. Williamson, Synthesis of phosphonate analogues of 1,3-bis-phosphoglyceric acid and their binding to yeast phosphoglycerate kinase, Bioorg. Med. Chem. Lett. 4 (1994) 2573-2578. 

Enolase also proved (72) to use as a substrate the arsonomethyl analogue of its substrate 2-phosphoglyceric acid, i.e., 3-arsono-2-(hy-droxymethyl)propionic acid, H203As—CH2—CH(—CH2—OH)—... 

Fructose bisphosphate is cleaved by action of an aldolase (reaction 4) to give glyceraldehyde 3-phosphate and dihydroxyacetone phosphate. These two triose phosphates are then equilibrated by triose phosphate isomerase (reaction 5 see also Chapter 13). As a result, both halves of the hexose can be metabolized further via glyceraldehyde 3-P to pyruvate. The oxidation of glyceraldehyde 3-P to the corresponding carboxylic acid, 3-phosphoglyceric acid (Fig. 17-7, reactions 6 and 7), is coupled to synthesis of a molecule of ATP from ADP and P . This means that two molecules of ATP are formed per hexose cleaved, and that two molecules of NAD+ are converted to NADH in the process. 

Figure 20.11 Conversion of 3-phosphoglyceric acid to serine. 3-Phosphoglyceric acid originates from dihydroxyacetone phosphate, a glycolysis intermediate.

PG = 3-phosphoglyceric acid G3P = glyceraldehyde 3-phosphatc DHAP = dihydroxyacetone phosphate FDP = fructose 1,6-diphosphate F6P = fructose 6-phosphate G6P = glucose 6-phosphate E4P = erythrose 4-phosphate X5P = xylulose 5-phosphate SDP = sedoheptulose 1,7-diphosphaie S7P = sedoheptulose 7-phosphate R5P = ribose 5-phosphate Ru5P = ribulose 5-phosphate RuDP = ribulose 1,5-diphosphate... 

Figure 8-13. Schematic illustration of Rubisco (ribulose-l,5-bisphosphate carboxylase/oxygenase) acting as the branch point for photosynthesis and photorespiration. All three of the organelles involved, but only a few of the biochemical steps, are indicated. ( represents phosphate. Note that 3-phosphoglycerate and glycolate refer to the dissociated forms of 3-phosphoglyceric acid and glycolic acid, respectively.)...

---