Tricarboxylic acid cycle enzyme complex (TCA cycle enzyme complex)

The **Tricarboxylic acid cycle enzyme complex** refers collectively to the set of eight core mitochondrial matrix enzymes that catalyze sequential reactions in the tricarboxylic acid (TCA) or citric acid/Krebs cycle. This central metabolic pathway oxidizes acetyl-CoA—derived from carbohydrates, fats, and proteins—to carbon dioxide while generating high-energy electron carriers NADH and FADH₂. These carriers feed electrons into the mitochondrial electron transport chain for ATP synthesis via oxidative phosphorylation. The TCA cycle also provides key biosynthetic precursors for amino acids, heme, and other molecules through its amphibolic nature[1][2][4]. Alterations in expression or activity of these enzymes have been implicated in diseases such as cancer—where intermediates like citrate and succinate modulate tumor metabolism—and neurodegenerative disorders like Alzheimer’s disease, where several TCA-related genes serve as potential biomarkers or therapeutic targets[3][6]. While individual components such as isocitrate dehydrogenase or succinate dehydrogenase may be targeted by drugs in certain contexts, there are no therapies directed at the entire multi-enzyme system due to its fundamental role in cell viability. **Note:** This entry describes a *complex* rather than a single molecular entity. For structured data purposes it may be preferable to refer instead to specific constituent enzymes such as "Isocitrate dehydrogenase," "Succinate dehydrogenase," etc., each with their own canonical names and properties. The term "Tricarboxylic acid cycle enzyme complex" is not standard nomenclature for a single druggable target but rather denotes an essential collection of metabolic catalysts.[1][2]

Other names

Citric acid cycle enzyme complexKrebs cycle enzyme complexTCA cycle enzymesCitric acid cycle enzymesKrebs cycle enzymes

Mechanisms are specific to individual enzymes within the complex; e.g., inhibition or activation of isocitrate dehydrogenase or succinate dehydrogenase.