GTP biosynthetic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the formation of GTP, guanosine triphosphate. [ISBN:0198506732]

The GTP biosynthetic process is a fundamental metabolic pathway responsible for the production of guanosine triphosphate (GTP), a crucial molecule in cellular signaling, energy metabolism, and protein synthesis. This process occurs in two main stages:

**1. Guanine Nucleotide Synthesis:**

* **De novo synthesis:** This pathway begins with the conversion of the precursor molecule inosine monophosphate (IMP) to guanosine monophosphate (GMP).
* **Salvage pathway:** Alternatively, GMP can be generated through the salvage pathway, where purine bases like guanine are recycled from degraded nucleic acids.

**2. Phosphorylation:**

* GMP is phosphorylated to guanosine diphosphate (GDP) by the enzyme nucleoside diphosphate kinase (NDPK).
* GDP is further phosphorylated to GTP by the enzyme nucleoside triphosphate kinase (NTPK).

**Detailed Description:**

**De Novo Synthesis:**
* IMP, the precursor molecule, is first converted to xanthosine monophosphate (XMP) by the enzyme IMP dehydrogenase (IMPDH).
* XMP is then converted to GMP by the enzyme GMP synthetase, using glutamine as the nitrogen source.

**Salvage Pathway:**
* Guanine is converted to guanosine by the enzyme purine nucleoside phosphorylase (PNP).
* Guanosine is then phosphorylated to GMP by the enzyme guanosine kinase.

**Phosphorylation:**
* NDPK catalyzes the transfer of a phosphate group from ATP to GDP, forming GTP.
* The GTP generated is essential for a wide array of cellular functions, including:
* **Signal transduction:** GTP acts as a molecular switch in G-protein coupled receptors (GPCRs), regulating downstream signaling pathways.
* **Protein synthesis:** GTP is required for the elongation and termination steps of protein translation.
* **Energy metabolism:** GTP is an energy-rich molecule used by certain enzymes, including those involved in gluconeogenesis.

**Regulation:**
* The GTP biosynthetic process is tightly regulated to maintain cellular GTP levels within a specific range.
* IMPDH, the key enzyme in the de novo pathway, is regulated by feedback inhibition from GMP and GTP.
* Cellular GTP levels are also influenced by the activity of enzymes involved in GTP hydrolysis, such as GTPases.'
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Proteins (7)

Compounds (205)