Phosphorylation by ATP

Figure 6.24 The function of the enzyme phosphofructokinase. (a) Phosphofructokinase is a key enzyme in the gycolytic pathway, the breakdown of glucose to pyruvate. One of the end products in this pathway, phosphoenolpyruvate, is an allosteric feedback inhibitor to this enzyme and ADP is an activator, (b) Phosphofructokinase catalyzes the phosphorylation by ATP of fructose-6-phosphate to give fructose-1,6-bisphosphate. (c) Phosphoglycolate, which has a structure similar to phosphoenolpyruvate, is also an inhibitor of the enzyme.

Similarly, the rate of inhibition of phosphoenzyme formation by diethylpyrocarbonate (DEPC) was much slower than the loss of ATPase activity [368], Even when the reaction approached completion with more than 90% inhibition of ATP hydrolysis, about 70% of the Ca -ATPase could still be phosphorylated by ATP (2.3nmoles of E P/mg protein). The remaining 30% of E P formation and the corresponding ATPase activity was not reactivated by hydroxylamine treatment, suggesting some side reaction with other amino acids, presumably lysine. When the reaction of the DEPC-modified ATPase with P-ATP was quenched by histidine buffer (pH 7.8) the P-phosphoenzyme was found to be exceptionally stable under the same conditions where the phosphoenzyme formed by the native ATPase underwent rapid hydrolysis [368]. The nearly normal phosphorylation of the DEPC-trea-ted enzyme by P-ATP implies that the ATP binding site is not affected by the modification, and the inhibition of ATPase activity is due to inhibition of the hydrolysis of the phosphoenzyme intermediate [368]. This is in contrast to an earlier report by Tenu et al. [367], that attributed the inhibition of ATPase activity by... 

The plasma membrane Ca2+-ATPase pump effects outward transport of Ca2+ against a large electrochemical gradient for Ca2+. The mechanism of the pump involves its phosphorylation by ATP and the formation of a high-energy intermediate. This basic mechanism is similar for both the plasma membrane and ER pumps however, the structures of these distinct gene products are substantially different. As discussed below, the ER pump, sometimes called a sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) pump, is inhibited potently by certain natural and synthetic toxins that do not affect the plasma membrane pump. The plasma membrane pump, but not the SERCA pump, is controlled in part by Ca2+ calmodulin, allowing for rapid activation when cytoplasmic Ca2+ rises. 

Figure 5.8 Active transport is achieved by phosphoiylation and dephosphorylation of the transporter. The dephosphorylated form has a high affinity for the molecules whereas the phosphorylated form has a low affinity. This is achieved by a conformation change resulting from phosphorylation by ATP and dephosphorylation via phosphate release.

This enzyme [EC 2.7.1.59] catalyzes the phosphorylation by ATP of iV-acetylglucosamine to generate ADP and A-acetylglucosamine 6-phosphate. The bacterial enzyme is also reported to act on glucose as well. 

Thiamine (vitamin Bi) is phosphorylated by ATP to thiamine pyrophosphate. This is a coenzyme for, among others, alpha-ketoglutarate dehydrogenase, transketolase and pyruvate dehydrogenase. Thiamine pyrophosphate is involved in fatty acid... 

The transporting protein in the sarcoplasmic membrane can be phosphorylated by ATP as well as by inorganic phosphate (cf.2,174 ). In the forward running mode of the pump, i. e. when the calcium pump accumulates calcium and concomitantly hydrolyzes ATP, the terminal phosphate residue of ATP is transferred to the transport protein. The reaction depends on the presence of calcium ions in the external medium. In the reverse mode of the pump inorganic phosphate is incorporated into the transport protein. This reaction is inhibited when calcium ions are present in the external medium,... 

The family of active transporters called P-type ATPases are ATP-driven cation transporters that are reversibly phosphorylated by ATP as part of the transport cycle phosphorylation forces a conformational change that is central to moving the cation across the membrane. All P-type transport ATPases have similarities in amino acid... 

Dihydroxyacetone phosphate is converted to glycer-aldehyde 3-phosphate by the glycolytic enzyme triose phosphate isomerase. Glyeeraldehyde is phosphorylated by ATP and triose kinase to glyeeraldehyde 3-phos-phate ... 

Modification of Individual Amino Acids The hydroxyl groups of certain Ser, Thr, and Tyr residues of some proteins are enzymatically phosphorylated by ATP (Fig. 

Have we checked all of the possibilities for the mechanism of biotin carboxylation Kruger and associates62 63 suggested that biotin, as a ureido anion, might add to bicarbonate to form a highly unstable intermediate which, however, could be phosphorylated by ATP (Eq. 14-10, steps a and b). This intermediate could undergo elimination of inorganic phosphate... 

The metabolic interconversions of glucose 1-P, glucose 6-P, and fructose 6-P are thought to be at or near equilibrium within most cells. However, the phosphorylation by ATP of fructose 6-P to fructose 1,6-P2... 

Fructose 6-phosphate is phosphorylated by ATP to form fructose 1,6-bisphosphate and ADP. The enzyme catalyzing this step is phospho-fructokinase (PFK). 

The aromatic amino acids, phenylalanine, tryptophan, and tyrosine, are all made from a common intermediate chorismic acid. Chorismic acid is made by the condensation of erythrose-4-phosphate and phosphoenol pyruvate, followed by dephosphorylation and ring closure, dehydration and reduction to give shikimic acid. Shikimic acid is phosphorylated by ATP and condenses with another phosphoenol pyruvate and is then dephosphorylated to give chorismic acid. 

Similarly to biosynthetic reaction, some of highly active inhibitors also can be phosphorylated by ATP in the active site of the enzyme (Scheme 8-3).92 In the case of phosphinothricin (28) and methionine sulfoximine (29), the formed phosphates are actual inhibitors of GS and are irreversibly bound to the protein.93... 

Phosphorylation by ATP, catalyzed by thiamin diphosphate kinase, which acts only on protein-bound thiamin diphosphate and... 

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