glycine biosynthetic process from serine

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the formation of glycine from other compounds, including serine. [GOC:go_curators]

The glycine biosynthetic process from serine is a crucial metabolic pathway for the production of glycine, an essential amino acid. This process occurs primarily in the mitochondria of eukaryotic cells and involves the following steps:

1. **Serine Hydroxymethyltransferase (SHMT) Activity:**
- SHMT is a key enzyme in this pathway. It catalyzes the reversible transfer of a one-carbon unit from serine to tetrahydrofolate (THF), forming glycine and methylenetetrahydrofolate (methylene-THF).
- This reaction requires pyridoxal phosphate (PLP), a coenzyme derived from vitamin B6, as a cofactor.
- The reaction can proceed in either direction, depending on the cellular needs for glycine or serine.

2. **Methylene-THF Reductase (MTHFR) Activity:**
- Methylene-THF reductase (MTHFR) is another enzyme involved in this process. It catalyzes the reduction of methylene-THF to 5,10-methylenetetrahydrofolate (5,10-methylene-THF).
- This reaction requires NADPH as a reducing agent.

3. **Tetrahydrofolate Reductase (THF Reductase) Activity:**
- Tetrahydrofolate reductase (THF reductase) is an essential enzyme responsible for maintaining adequate levels of THF, a crucial cofactor in various metabolic pathways.
- It catalyzes the reduction of dihydrofolate (DHF) to THF using NADPH.
- This reaction ensures a continuous supply of THF for the SHMT reaction, which is crucial for the synthesis of glycine from serine.

**Overall Reaction:**

Serine + THF + NADPH -u003e Glycine + 5,10-methylene-THF + NADP+ + H2O

**Importance of Glycine Biosynthesis from Serine:**

* **Essential amino acid production:** Glycine is a fundamental building block for proteins and is involved in numerous biological processes, including collagen synthesis, DNA replication, and neurotransmitter function.
* **One-carbon metabolism:** This pathway contributes to one-carbon metabolism by providing methylene-THF, a crucial intermediate in the synthesis of purines, thymine, and methionine.
* **Regulation of cellular metabolism:** The flux through this pathway is tightly regulated by various factors, including the availability of substrates, cofactors, and the activity of key enzymes, ensuring balanced cellular metabolism.

**Clinical Relevance:**

* **Deficiencies in SHMT activity:** Genetic defects in SHMT can lead to various metabolic disorders, including hypermethioninemia and homocystinuria.
* **Folic acid deficiency:** Folic acid is essential for the synthesis of THF, a cofactor for SHMT. Deficiencies in folic acid can disrupt glycine production and contribute to neural tube defects in fetuses.

**Summary:** The glycine biosynthetic process from serine is a vital metabolic pathway that provides a critical source of glycine, a crucial amino acid. It is tightly regulated by a series of enzymatic reactions involving SHMT, MTHFR, and THF reductase. This pathway contributes to one-carbon metabolism and plays a role in various cellular functions and health outcomes.'
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Proteins (2)

Compounds (10)