Citric acid, cis-aconitic acid, and isocitric acid are the first three metabolites in the Krebs Citric Acid energy production cycle, which operates in the mitochondria of your cells.
Citrate, cis-Aconitate (and Isocitrate) are involved in both energy production and removal of toxic ammonia.
High levels can indicate ammonia toxicity. Chronic loss of these valuable compounds can contribute to loss of organ reserve and disturbances in neurological function. If they are low they can indicate a need for essential amino acids, especially arginine.
If Citrate is on the low end of the optimal range:
This key component of the citric acid cycle is formed inside the mitochondria from acetyl-coenzyme A and oxaloacetic acid by the enzyme citrate synthase. Succinate excess, as may occur with infection or intestinal dysbiosis (from bacterial transamination of non-absorbed glutamine), can inhibit citrate synthase. Citric acid can be low if cellular glucose or pyruvate is deficient or if pyruvate is elevated due to impairment of the pyruvate dehydrogenase complex that catalyzes the conversion of pyruvate into acetyl CoA. This transformation requires vitamin B1 as thiamin pyrophosphate, vitamin B2 as FAD, vitamin B3 as NAD, lipoic acid, magnesium and ATP.
Impaired beta-oxidation of fatty acids, as occurs with carnitine deficiency, can reduce levels of acetyl-CoA and citrate, especially in the early fasting state (12-48 hours after eating). Carnitine is necessary to transport long-chain fatty acids across the outer mitochondrial membrane for subsequent oxidation. Citric acid can also be low if oxaloacetic acid (its precursor) is insufficient. Oxaloacetic acid may be formed by oxidizing malic acid, or by transaminating aspartate. The first reaction requires B3 as NAD and the second requires B6 as pyridoxal 5-phosphate. Citric acid formation may also be low if pyruvate carboxylase is weak or in multiple carboxylase deficiency (pyruvic acid should be elevated). Pyruvate carboxylase requires biotin, ATP, magnesium and manganese. Additionally, low urinary citrate can occur with increased proximal tubular resorption in the kidneys that occurs in metabolic acidosis. This leads to hypocitraturia and can predispose the person to kidney stone formation.
Citrate
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