Phosphate, inorganic esterification

Esterification. The hydroxyl groups of sugars can react with organic and inorganic acids just as other alcohols do. Both natural and synthetic carbohydrate esters are important in various apphcations (1,13). Phosphate monoesters of sugars are important in metabohc reactions. An example is the enzyme-catalyzed, reversible aldol addition between dibydroxyacetone phosphate [57-04-51 and D-ylyceraldehyde 3-phosphate [591-57-1 / to form D-fmctose 1,6-bisphosphate [488-69-7],... 

In this chapter, the words cleavage and de-esterification are often used to make it clear that reactions other than hydrolysis may be involved in the breakdown of some inorganic esters. This is particularly true for nitrates, and various phosphates and phosphonates, as discussed in the relevant sections. 

Phosphorylation is an effective way to increase negative charges in a protein molecule and thereby to improve functionality, particularly solubility. Either O- or N-esterification reactions can transfer inorganic phosphate (P )... 

Polyvinyl alcohol undergoes reactions typical of a compound with secondary hydroxy groups, such as esterification. It decomposes in strong acids, and softens or dissolves in weak acids and alkalis. It is incompatible at high concentration with inorganic salts, especially sulfates and phosphates precipitation of polyvinyl alcohol 5% w/v can be caused by phosphates. Gelling of polyvinyl alcohol solution may occur if borax is present. 

There are two ways to obtain polyvinyl esters. One is polymerization of the corresponding monomer, and the other is by esterification of PVA [94]. In addition to organic esters, some inorganic esters such as nitrate, sulfate, and phosphate also have been synthesized by esterification [94]. 

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... 

Succinyl CoA-ADP phosphorylase —conversion of succinyl CoA to succinate with concomitant esterification of inorganic phosphate. 

The most significant aspect of the citric-acid cycle is the process by which ATP formation from ADP and inorganic phosphate is tied up with electron transfer reactions. The oxidation of a-ketoglutarate to succinate by oxygen involves the esterification of four molecules of inorganic phosphate per atom of oxygen. - It has been assumed that four oxidoreduc-... 

Mitochondrial studies have uncovered a whole group of substances, e.g., 2,4-dinitrophenol, gramicidin, and aureomycin, which can dissociate esterification of inorganic phosphate from the oxidation process. These substances have become known as uncoupling agents. There is some evidence that they uncouple by dephosphorylating the primary acceptor complex before the phosphoryl group can be transferred to ADP. ... 

Inorganic phosphate is not required for levan synthesis, and it has no effect on the rate of reaction no esterification of phosphate can be detected. It is therefore considered that levan synthesis is the result of the transfer of fructose units from sucrose to a suitable acceptor through the mediation of a fructose-enzyme complex. 

The esterification of inorganic phosphate which occurs in green plants in the light and appears to be intimately linked to photosynthesis, will be discussed in another section of this review. The reviewers believe that this light dependent phosphorylation may proceed in part through a mechanism similar to that of oxidative phosphorylation in heterotrophic organisms. The occurrence of an oxidative phosphorylation linked to the reoxidation of pyridine nucleotides as described by Lehninger (222) has only recently been found in plants. Its discovery by Bonner and Millerd (51) was... 

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