Isocitric lyase

Isocitrate Lyase Short-Circuits the TCA Cycle by Producing Glyoxylate and Succinate... 

McKinney JD, Honer zu Bentrup K, Munoz-Elias EJ et al. Persistence of Mycobacterium tuberculosis in macrophages and mice requires the glyoxylate shunt enzyme isocitrate lyase. Nature 2000 406[6797] 735—738. 

HTHICLR helix turn helix isocitrate lyase regulation B 0(0) 0(0) ... 

Fig. 9. Pathway duplication the methyl citrate cycle and the glyoxylate shunt. A pathway for acetate metabolism in E. coli that uses the glyoxylate shunt is depicted on the right. Part of the methyl citrate cycle, a pathway for propionate metabolism, is depicted on the left. The pathways are analogous furthermore, three of the four steps are catalyzed by homologous enzymes. PrpE (propionyl-CoA synthase) is homologous to AcsA (acetyl-CoA synthase). PrpC (2-methyl-citrate synthase) is homologous to GltA (citrate synthase). PrpB (2-methyl-isocitrate lyase) is homologous to AceA (isocitrate lyase). The third step in the methyl citrate cycle has been suggested to be catalyzed by PrpD the second half of the reaction (the hydration) can be catalyzed by aconitase.

COMPUTER ALGORITHMS SOFTWARE ISOCHORISMATE SYNTHASE ISOCITRATE DEHYDROGENASE ISOCITRATE LYASE "ISO-COOP,"... 

The same intermediates of glycolysis and the citric acid cycle that activate isocitrate dehydrogenase are allosteric inhibitors of isocitrate lyase. When energy-yielding metabolism is sufficiently fast to keep the concentrations of glycolytic and citric acid cycle intermediates low, isocitrate dehydrogenase is inactivated, the inhibition of isocitrate lyase is relieved, and isocitrate flows into the glyoxylate pathway, to be used in the biosynthesis of carbohydrates, amino acids, and other cellular components. 

The glyoxylate cycle is active in the germinating seeds of some plants and in certain microorganisms that can live on acetate as the sole carbon source. In plants, the pathway takes place in glyoxysomes in seedlings. It involves several citric acid cycle enzymes and two additional enzymes isocitrate lyase and malate synthase. 

The first unique enzyme of the important glyoxy-late pathway (Chapter 17), isocitrate lyase, cleaves isocitrate to succinate and glyoxylate (Eq. 13-41).228 The carboxylate group that acts as electron acceptor would presumably be protonated by the enzyme. 

A key enzyme in the glyoxylate cycle is isocitrate lyase, which cleaves isocitrate (Eq. 13-40) to succinate and glyoxylate. The latter is condensed with a second acetyl group by the action of malate synthase (Eq. 13-38). The L-malate formed in this reaction is dehydrogenated to the regenerating substrate oxalo-... 

An acetyl-CoA-glyoxylate cycle, which catalyzes oxidation of acetyl groups to glyoxylate, can also be constructed from isocitrate lyase and citric acid cycle... 

Topic LI). Thus, animals cannot convert fatty acids into glucose. In contrast, plants have two additional enzymes, isocitrate lyase and malate synthase, that enable them to convert the carbon atoms of acetyl CoA into oxaloacetate. This is accomplished via the glyoxylate pathway, a route involving enzymes of both the mitochondrion and the glyoxysome, a specialized membranous plant organelle. 

Isocitrate lyase and malate synthase. Isocitrate lyase catalyzes the cleavage of isocitrate to succinate and glyoxylate malate synthase catalyzes the condensation of glyoxylate and acetyl-CoA to yield malate. 

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