Phospho enol pyruvate

From Sigma 3-aminoethylcarbazole (AEC) acrylamide/bis-acrylamide (30%) 37.5 1 amino acids alumina bentonite benzamidine bovine fiver tRNA bovine serum albumin (BSA) creatine phosphate (CP) diethyl pyrocarbonate (DEPC) dithiothreitol (DTT) Escherichia coli MRE600 tRNA pyrophosphatase (Ppase) Ca++ salt of folinic acid, (5-formyl THF) IIHPHS K salt of phospho-enol pyruvic acid, (PEP) creatine phospho kinase (CPK) protease inhibitor cocktail for fungal and yeast extracts phenylmethylsulfonyl fluoride (PMSF) spermidine trihydrochloride Tween 20. 

This leaves only one compound which must be phospho enol pyruvate (PEP) as compound (vii). 

In the cytoplasm, oxaloacetate is reformed and then converted into phospho-enol pyruvate by a GTP-dependent PEP car-bo)Q/kinase. The subsequent steps up to fructose 1,6-bisphosphate represent the reverse of the corresponding reactions involved in glycolysis. One additional ATP per C3 fragment is used for the synthesis of 1,3-bisphos-phoglycerate. 

For the phosphotransferase system there is no problem in identifying the energy source for the establishment of the thermodynamic potential gradient. It is apparent that a high-energy phosphate bond in phospho-enol-pyruvate is the immediate source of the energy responsible for the vectorial translocation of the sugar molecule across the membrane (17). 

Thus, redox-dehydration, catalysed by enolase Gives P.E.P. formation and bond energy raise So phospho-enol pyruvate reacts with ADP The kinase making ATP, but not reversibly. 

Bromopyruvic acid inhibits S-deoxy-D-erj t ro-hexulosonate 6-phosphate aldolase " and 3-deoxy-D-ar-a6mo-heptulosonate 7-phosphate synthetase " in a similar way. The enzymes are protected from inhibition by pyruvate and phospho-enol pyruvate respectively. Since aldolases must possess a nucleophilic group to initiate the reaction, this type of inhibition should be a general property of aldolases. 

Fig. (1). Phenolic metabolism. PEP (phospho enol pyruvate) E4P (erythrose 4-phosphate) DAHP (3-Deoxy-D-arabino-heptulosonate 7-phosphate) PAL (phenylalanine ammonia lyase). Stress transcriptionally activates the key enzymes of phenolic metabolism (PAL and DAHP synthase).

Fig. 3.17. Optimized separation of organic phosphate standards by ion-pair chromatography with ultraviolet detection (AMP, ADP, ATP = adenosine mono-, di- and triphosphate P-Crea = creatine phosphate PEP = phospho(enol)pyruvate AUS = absorbance units = — log (% transmission). The small peak at 4 min is phosphate. Conditions 7.75 mMTris buffer, pH 6.9 4 mM tetrabutylammonium ion pair reagent 22.5% acetonitrile.

Reaction 1 depicts the conversion of phospho-enol pyruvate to pyruvate. 

M phospho(enol)pyruvic acid K salt (PEP) (Sigma-Aldrich), adjusted to pH 7.0 with KOH. 

In the continuous, substrate-regenerating assay, Dnml hydrolyzes GTP into GDP and inorganic phosphate. As shown in Fig. 1, GTP is regenerated from GDP and phospho(enol)pyruvate (PEP) by pyruvate kinase. The pyruvate produced by this regenerative reaction is reduced to lactate by the enzyme lactate dehydrogenase, using NADH as a cosubstrate. NADH depletion is measured by continuously monitoring a decrease in absorbance at 340 nm over time and is directly proportional to GTP hydrolysis. 

Acetaldehyde + CO2 <---------Pyruvic, phospho-enol-pyruvic acid ... 

Fig. 9. Effect of glucagon on hepatic gluconeogenesis. Reversible reactions are indicated by double arrows, irreversible reactions by simple arrows. A crossed arrow indicates an inhibited reaction and an asterisk an enhanced reaction. PC = pyruvate carboxylase PK = pyruvate kinase PDH = pyruvate dehydrogenase PEPCK = phospho-enol pyruvate cocarboxykinase PFK = phosphofructokinase. (Partially redrawn from Ruderman et al Arch. Internal. Med., 123, 299,1969.)...

In the next steps of glycolysis, the phosphate on the 3-position of the 3-phosphoglycerate is transferred to the hydroxyl residue at position 2. Removal of the elements of water from 2-phosphoglycerate results in the formation of an enolic phosphate compound, phospho(enol)pyruvate... 

The UDP-Gal epimerase system was also one of the early methods to employ pyruvate kinase (PK EC 2.7.1.40) for the conversion of UDP to UTP, with the simultaneous formation of pyruvate from phospho(enol)pyruvate (PEP). Previous kinase systems employed were either more expensive (nucleoside diphosphate kin-ase(EC 2.7.4.6)/ATP) or were thermodynamically less favorable (acetate kinase(EC 2.7.2.1)/acetyl phosphate). Another potentially usefid kinase system has recently been described. Noguchi and Shiba have utilized polyphosphate kinase (PPK) for the formation of UTP from UDP in a UDP-Gal recycling system [13]. Previously, PPK was shown to catalyze the reversible transfer of phosphate from ATP to ADP. Recently, it has been discovered that PPK will also accept other NDP and NTP substrates. For application to recycling systems, poly(phosphate) is more affordable than PEP as a phosphoryl donor. Synthetically, replacement of PK with PPK in the UDPGE-based recycling system efficiently provided LacNAc from GlcNAc on a multi-gram scale. 

This route, often called the shikimic acid pathway involves the condensation of phosphoenolpyruvate (2) and a 4-carbon sugar erythrose-4-phosphate (1) which is derived from the pentose phosphate pathway. The product of this reaction is converted to shikimic acid (3). Phosphorylation of shikimic acid to yield 5-phosphoshikimic acid (4) is followed by the addition of another molecule of phospho-enol pyruvate (2) which results in the synthesis of prephenic acid (5). Aromatization of the prephenic acid can give rise to phenylpyruvic acid (6) which upon transamination becomes phenylalanine. The carbon skeletons of the other aromatic amino acids, tryptophane and tyrosine are also synthesised via the shikimic acid pathway as is lignin and many of the aromatic secondary products described in Chapter 6. 

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