nucleotide metabolic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways involving a nucleotide, a nucleoside that is esterified with (ortho)phosphate or an oligophosphate at any hydroxyl group on the glycose moiety; may be mono-, di- or triphosphate; this definition includes cyclic nucleotides (nucleoside cyclic phosphates). [GOC:ma]

Nucleotide metabolism is a fundamental biological process that encompasses the synthesis, degradation, and interconversion of nucleotides, the building blocks of DNA and RNA. It is an essential process for life, playing vital roles in genetic information storage and transmission, energy production, and cellular signaling.

**Nucleotide Synthesis:**

* **De novo synthesis:** This pathway starts with simple precursors like amino acids, ribose-5-phosphate, and CO2. These precursors are converted into purine and pyrimidine bases, which are then attached to ribose-5-phosphate to form nucleotides.
* **Salvage pathway:** This pathway recycles pre-existing purine and pyrimidine bases from degraded nucleic acids. These bases are then converted into nucleotides.

**Nucleotide Degradation:**

* **Purine degradation:** Purine nucleotides are broken down into uric acid, which is excreted in the urine.
* **Pyrimidine degradation:** Pyrimidine nucleotides are broken down into β-alanine and β-aminoisobutyrate, which are further metabolized.

**Interconversion of Nucleotides:**

* **Ribonucleotide reductase:** This enzyme converts ribonucleotides (with a ribose sugar) to deoxyribonucleotides (with a deoxyribose sugar), which are used in DNA synthesis.
* **Phosphorylation and dephosphorylation:** Nucleotides can be interconverted by adding or removing phosphate groups, affecting their energy content and activity.

**Regulation of Nucleotide Metabolism:**

* **Feedback inhibition:** The end products of nucleotide synthesis can inhibit the enzymes involved in the early steps of their own synthesis.
* **Hormonal control:** Hormones like insulin and glucagon can influence nucleotide metabolism.
* **Genetic factors:** Mutations in genes involved in nucleotide metabolism can lead to genetic disorders.

**Biological Importance:**

* **DNA replication and repair:** Nucleotides are essential for DNA synthesis and repair, ensuring the integrity of genetic information.
* **RNA transcription and translation:** RNA is synthesized using nucleotides, and plays a crucial role in protein synthesis.
* **Energy metabolism:** Nucleotides like ATP and GTP are involved in energy transfer and cellular processes.
* **Cellular signaling:** Nucleotides act as signaling molecules, involved in cell communication and regulation.

**Disorders of Nucleotide Metabolism:**

* **Lesch-Nyhan syndrome:** A rare genetic disorder caused by a deficiency in the enzyme hypoxanthine-guanine phosphoribosyltransferase, leading to uric acid accumulation.
* **Severe combined immunodeficiency (SCID):** Certain types of SCID are caused by defects in enzymes involved in nucleotide metabolism, affecting immune function.
* **Cancer:** Dysregulation of nucleotide metabolism can contribute to cancer development and progression.
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Proteins (2)

Compounds (30)