citrulline biosynthetic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the formation of citrulline, N5-carbamoyl-L-ornithine, an alpha amino acid not found in proteins. [ISBN:0198506732]

The citrulline biosynthetic process is a crucial metabolic pathway that produces citrulline, an amino acid essential for various physiological functions. This process primarily occurs in the liver and kidney, with significant contributions from the small intestine. The main source of citrulline is the breakdown of arginine, which is catalyzed by arginase.

The process begins with the hydrolysis of arginine by arginase, leading to the formation of citrulline and urea. This reaction takes place in the cytoplasm of liver cells, where arginase is primarily localized. Citrulline then enters the mitochondria, where it is further converted to arginine by the urea cycle. The urea cycle is a metabolic pathway responsible for the removal of ammonia from the body, a toxic byproduct of protein metabolism.

In addition to the arginase-mediated pathway, citrulline can also be produced in the small intestine through the catabolism of glutamine by the enzyme glutaminase. This pathway contributes a significant amount of citrulline to the circulation.

Citrulline is a precursor to arginine, which is essential for numerous cellular functions, including protein synthesis, wound healing, and immune function. Moreover, citrulline plays a role in nitric oxide (NO) production, a vasodilator that regulates blood pressure and blood flow. Citrulline itself also exhibits vasodilatory properties.

The citrulline biosynthetic process is tightly regulated, with various factors influencing its activity. These include nutritional intake, hormonal signaling, and cellular energy status. Dysregulation of this pathway has been linked to various health conditions, including cardiovascular disease, liver disease, and immune dysfunction.

In summary, the citrulline biosynthetic process is a vital metabolic pathway that produces citrulline, a crucial amino acid involved in various cellular and physiological functions. This process is essential for maintaining normal liver and kidney function, regulating blood pressure, and supporting immune responses.'
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Proteins (2)

Compounds (5)