Phosphate, esterification

Braunstein and Kritzman discovered transamination. Early demonstrations that phosphate esterification was linked to oxygen uptake. 

Cross-linking Monostarch phosphate - Esterification with ortho-phosphoric acid, or sodium or potassium ortho-phosphate, or sodium tripolyphosphate Distarch phosphate - Esterification with sodium trimetaphosphate or phosphorus oxychloride Phosphated distarch phosphate - Combination oftreatments for monostarch phosphate and distarch phosphate... 

Dual modification Acetylated distarch phosphate - Esterification by sodium trimetaphosphate or phosphorus oxychloride combined with esterification by acetic anhydride or vinyl acetate Hydroxypropyl distarch phosphate - Esterification by sodium trimetaphosphate or phosphorus oxychloride combined with etherification by propylene oxide... 

Krebs Cycle and Fatty Acid Oxidation. A possible role of Krebs cycle intermediates in supporting fatty acid oxidation is now apparent. Complete oxidation to CO2 requires oxalacetate to introduce acetyl CoA into the citric acid cycle. But even the formation of acetoacetate requires the continued generation of ATP to support the activation of fatty acids. The transfer of electrons from fatty acid to oxygen is coupled with phosphate esterification, so that fatty acid oxidation has the theoretical capacity to be self-supporting. In the crude systems that contain all of the essential factors for fatty acid oxidation, fatty acid activation must compete with other reactions for the available ATP, and maximum rates of oxidation occur only when additional ATP is generated through operation of the Krebs cycle. 

Another approach to the nature of the phosphate esterification reaction has been made with the use of isotope exchange methods. Boyer et al. and Swanson have shown that an exchange reaction between ATP and inorganic P is catalyzed by anaerobic mitochondria, and suggest that the exchange represents a reversible step in the process of oxidative phosphorylation. Similar conclusions were reached by Cohn and Drys-dale, who found in experiments with mitochondria that the oxygen of... 

The nucleic acids are polymers of a large number of appropriate mononucleotide residues (base-sugar-phosphate) joined by internucleotidic ribose phosphate esterifications the polymeric linkage is the phosphate ester bond. Their biological importance is evident from the fact that two types, called RNA and DNA, are found in all cells and some viruses. Although DNA appears to exist exclusively within the cell nucleus, RNA (though more abundant in the cytoplasm) also occurs to some extent in the nucleus. RNA represents the sole nucleic acid type associated with the plant viruses 156) whereas the bacterial viruses, which are rich in DNA, apparently lack RNA 157). (For histochemical identification, see Chapter XI.)... 

Glutamic acid is oxidized to completion by the kidney and liver cyclophorase suspensions of Green and co-workers. The oxidation proceeds by way of a-ketoglutarate, and the cyclophorase complex contains the enzymes necessary for the aerobic and anaerobic synthesis of glutamate from a-ketoglutarate and ammonia. The enzyme preparation is specific for L-glutamate D-glutamate appears to exert an inhibitory effect on the oxidation of the L-isomer. Phosphate esterification accompanies the oxidation. 

The P 0 ratio for the oxidation of malate and citrate is 3, whereas that for succinate is 2. At present there is detailed knowledge of only one oxidative step which can be linked with phosphate esterification, viz., oxidation of a-ketoglutarate to succinyl CoA. The succinate activation enzyme catalyzes reaction 5 of the following sequence initiated by the Kg.d. ... 

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