Cis-aconitic acid

Acid yellow (Aquashade), herbicide/algicide for aquaculture in U.S., 3 214t Acitretin, 25 790 a-c Josephson effect, 15 750 Aclame, 24 232 ac losses, 23 845-846 Acne, vitamin A treatments for, 25 789 cis-Aconitic acid, in citric acid cycle, 6 633 Aconitine, 2 103... 

There have been a number of isolated studies of metal-ion catalyzed nucleophilic reactions of other groupings. Particularly interesting is the induced nucleophilic attack on olefins. Hydration is normally very sluggish. Enzymes can speed up such reactions. Aconitase, an iron-containing enzyme, catalyzes the isomerization of citric acid to isocitric acid, through the intermediacy of cis-aconitic acid. A possible mechanism has been suggested based on the following Co(III) model chemistry. Rapid cyclization of the maleate ester produces Ai and AS chelated malate half ester ... 

Figure 1. Total ion current of n-butyl esters of the acidic fraction from non-sterile leaf washings of C. sativa. Key 1 = oxalic acid 2 = malonic acid 3 = maleic acid 4 = succinic acid 5 = fumaric acid 6 = alpha-ketoglutaric acid 7 = cis-aconitic acid 8 = citric acid (19)-...

The enzyme aconitase catalyzes the isomerization of citric acid to isocitric acid via the intermediate cis-aconitic acid (Scheme 46),530 and various attempts have been made to model this reaction.21 The cobalt Ill) complexes derived from methyl maleate (171) and methyl fumarate (172) have been prepared531 to study intramolecular attack by coordinated hydroxide on the alkene. Generation of the hydroxo species of the maleic acid complex leads to rapid cyclization to give the... 

The actual function of aconitic acid in the plant physiology is not clearly understood. Cis-aconitic acid undoubtedly is present to a certain extent in the plant because of its role in the citric acid cycle but the factors which cause the accumulation of comparatively large quantities of aconitic acid have not been clearly defined. Whether the concentration of aconitic acid which is formed in the plant is the cts-form exclusively or is a mixture of the cis- and the trans- acids is also unknown. Balch, Broeg and Ambler,37 in their investigations, reported considerable variation in the aconitic acid content of various crusher juices of Louisiana... 

Gawron, O., Mahajan, K.P. (1966). a-Methyl-cis-aconitic acid, cis-aconitase substrate. II. Substrate properties and aconitase mechanism. Biochemistry 5 2343-50. 

In general, all the bonds mentioned above may be hydrolyzed, although the rate of hydrolysis may vary from very fast to almost insignificant. For instance, the rate of uncatalysed hydrolysis of amide bonds is relatively low but it can be increased by the introducticm of specific groups adjacent to the amide bond Shen and Ryser showed that amides of cis-aconitic acid are cleaved when entering the lysosomal compartment (Ihey are stable at pH 7 and labile at pH 4-5). 

Kanamasa, S., Dwiarti, L., Okabe, M., and Park, E.Y. (2008) Cloning and functional characterization of the cis-aconitic acid decarboxylase (CAD) gene from Aspergillus terreus. Appl Microbiol Biotechnol, 80, 223—229. 

Martins and Lynen and Friedrich-Freksa and Martius expressed doubts on the intermediary formation of cis-aconitic acid because they failed to find a lag period when measuring the enzyme kinetics of the conversion of citrate into isocitrate. If the conversion was represented by the scheme... 

Thermoanalytical characteristics of citric acid were also studied by Trask-Morrell and Kottes Andrews [74] in the 60-600 °C temperature range. They found that anhydrous citric acid melted at 152-154 °C and then was decomposed at 228-242 °C. The weight loss of about 96 % of sample size was observed (in an apparent single peak), and at 575 °C, the residue of sample was very small. Thermal analysis of binary systems included in the Krebs tricarboxylic acids cycle was performed by UsoTtseva et al. [75-78]. They investigated systems of fumaric acid, malic acid, succinic acid, cis-aconitic acid and a-ketoglutaric acid with citric acid. They... 

Usol tseva VA, Pobedinskaya AI, Kobenina NM (1971) Thermographic analysis of intermediates of the Krebs triearboxylic acid cycle and their systems. 4. Thermographie analysis of the malic—citric acid system. Izv ss Ucheb Zaved Khimiya Khim Teehnol 14 698-700 Usol tseva VA, Pobedinskaya AI, Kobenina NM (1972) Thermal analysis of metabolites of the Krebs tricarboxylie aeid eycle and their systems. 6. Thermal analysis of the eitrie aeid— cis-aconitic acid and citric acid—a-ketoglutaric acid systems. Izv Vyss Ueheb Zaved Khimiya Khim Teehnol 15 1824—1827... 

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