citrate metabolic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways involving citrate, 2-hydroxy-1,2,3-propanetricarboyxlate. Citrate is widely distributed in nature and is an important intermediate in the TCA cycle and the glyoxylate cycle. [ISBN:0198506732]

The citrate metabolic process is a central hub in cellular metabolism, encompassing a series of enzymatic reactions that involve the formation, utilization, and degradation of citrate. Citrate is a six-carbon tricarboxylic acid that plays a crucial role in various metabolic pathways, including the citric acid cycle (also known as the Krebs cycle or tricarboxylic acid cycle), fatty acid biosynthesis, and gluconeogenesis.

**Citric Acid Cycle:** Citrate is a key intermediate in the citric acid cycle, a central metabolic pathway that occurs in the mitochondria of eukaryotic cells and the cytoplasm of prokaryotic cells. The cycle begins with the condensation of acetyl-CoA (a two-carbon unit derived from carbohydrates, fats, or proteins) with oxaloacetate (a four-carbon molecule), forming citrate. Citrate is then subjected to a series of enzymatic reactions, resulting in the production of ATP, NADH, FADH2, and carbon dioxide. The cycle is a major source of energy for cells, providing electrons for oxidative phosphorylation and generating ATP, the primary energy currency of the cell.

**Fatty Acid Biosynthesis:** Citrate also plays a vital role in the synthesis of fatty acids, a process that occurs in the cytoplasm. Citrate is transported from the mitochondria to the cytoplasm, where it is cleaved by ATP citrate lyase into acetyl-CoA and oxaloacetate. The acetyl-CoA is then used as a building block for the elongation of fatty acid chains.

**Gluconeogenesis:** In times of low blood glucose levels, the body can synthesize glucose from non-carbohydrate sources through a process called gluconeogenesis. Citrate, through its conversion to oxaloacetate, contributes to the production of glucose by providing a precursor for the gluconeogenic pathway.

**Regulation of Citrate Metabolism:** The activity of the enzymes involved in citrate metabolism is tightly regulated to ensure that the cell's energy needs are met and that metabolic pathways are coordinated. Factors that influence citrate metabolism include the availability of substrates, the levels of cellular energy (ATP), and hormonal signals.

**Metabolic Disorders:** Disruptions in citrate metabolism can lead to various metabolic disorders. For instance, defects in enzymes involved in the citric acid cycle can cause a buildup of citrate and other intermediates, leading to metabolic acidosis. Similarly, disruptions in fatty acid synthesis or gluconeogenesis due to problems with citrate metabolism can have significant consequences for energy production and glucose homeostasis.

In summary, the citrate metabolic process is a complex and essential pathway that plays a pivotal role in energy production, biosynthesis, and metabolic regulation. Understanding this process is crucial for comprehending cell function and for diagnosing and treating metabolic disorders.'
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