Carboxyl phosphate bond

Plant. In plants, mevinphos is hydrolyzed to phosphoric acid dimethyl ester, phosphoric acid, and other less toxic compounds (Hartley and Kidd, 1987). In one day, the compound is almost completely degraded in plants (Cremlyn, 1991). Casida et al. (1956) proposed two degradative pathways of mevinphos in bean plants and cabbage. In the first degradative pathway, cleavage of the vinyl phosphate bond affords methylacetoacetate and acetoacetic acid, which may be precursors to the formation of the end products dimethyl phosphoric acid, methanol, acetone, and carbon dioxide. In the other degradative pathway, direct hydrolysis of the carboxylic ester would yield vinyl phosphates as intermediates. The half-life of mevinphos in bean plants was 0.5 d (Casida et ah, 1956). In alfalfa, the half-life was 17 h (Huddelston and Gyrisco, 1961). 

The formation of 1,3-bisphosphoglycerate involves the synthesis of a high-energy phosphate bond as the aldehyde of glyceraldehyde 3-phosphate is oxidized to a carboxylic acid and then phosphorylated by reaction with inorganic phosphate. 

The AG° values for the hydrolysis of any P - O - P bond of ATP, inorganic pyrophosphate, or any acyl CoA thiolester are all about -34 kj / mole, while the corresponding figure for the hydrolysis of a mixed carboxylic phosphate anhydride is about -55 kj / mole. Calculate the value of AG° for the following reaction describing the activation of fatty acids to the fatty acyl adenylate. 

Hydrophilic molecules are composed of ions (such as sulphonate, sulphate, carboxylate, phosphate and quaternary ammonium), polar groups (such as primary amines, amine oxides, sulphoxides and phosphine oxide) and non-polar groups with electronegative atoms (such as oxygen atom in ethers, aldehydes, amides, esters and ketones and nitrogen atoms in amides, nitroalkanes and amines). These molecules associate with the hydrogen bonding network in water. 

The chemical behavior of DNA is primarily what would be expected on the basis of its structure. The sugar-phosphate backbone is held together by phosphate ester bonds. These bonds are not too different from carboxylic ester bonds. Thus, the phosphodiester... 

Ionic interactions arise from electrostatic attraction between two groups of opposite charge. These bonds are formed between positively charged (o -ammonium, -ammonium, guanidinium, and imidazolium) side chains and negatively charged (ionized forms of a-carboxyl, j6-carboxyl, y-carboxyl, phosphate, and sulfate) groups. 

The answer is a. (Murray, pp 190—198. Sci ivei, pp 1521—1552. Sack, pp 121-138. Wilson, pp 287-317.1 In the formation of phosphoenolpyruvate during gluconeogenesis, oxaloacetate is an intermediate. In the first step, catalyzed by pyruvate carboxylase, pyruvate is carboxylated with the utilization of one high-energy ATP phosphate bond ... 

Fig. 20.18. Pyruvate carboxylase reaction. Pyruvate carboxylase adds a carboxyl group from bicarbonate (which is in equihbrium with CO2) to pyruvate to form oxaloacetate. Biotin is used to activate and transfer the CO2. The energy to form the covalent biotin-C02 complex is provided by the high-energy phosphate bond of ATP, which is cleaved in the reaction. The enzyme is activated by acetyl CoA.

Water molecules will interact strongly with surfaces containing hydrophilic surface groups, such as hydroxyl, carboxyl, phosphate, and other hydrogen-bonding molecules. Simulation studies investigating the water structure within a few nanometres of a hydrophilic... 

Fig. 10. Pharmacophores for angiotension-converting enzyme. Distances in nm. (a) The stmcture of a semirigid inhibitor and distances between essential atoms from which one pharmacophore was derived (79). (b) In another pharmacophore, atom 1 is a potential zinc ligand (sulfhydryl or carboxylate oxygen), atom 2 is a neutral hydrogen bond acceptor, atom 3 is an anion (deprotonated sulfur or charged oxygen), atom 4 indicates the direction of a hydrogen bond to atom two, and atom 5 is the central atom of a carboxylate, sulfate, or phosphate of which atom 3 is an oxygen, or atom 5 is an unsaturated carbon when atom 3 is a deprotonated sulfur. The angle 1- -2- -3- -4 is —135 to —180° or 135 to 180°, and 1- -2- -3- -5 is —90 to 90°.

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