Serine hydroxymethyltransferase

Definition

Serine hydroxymethyltransferase is an enzyme that catalyzes the conversion of serine and tetrahydrofolate to glycine and 5,10-methylenetetrahydrofolate. This enzyme plays a crucial role in one-carbon metabolism, facilitating the transfer of a one-carbon unit, which is essential for various biosynthetic pathways, including the synthesis of nucleotides and amino acids.

5 Must Know Facts For Your Next Test

1. Serine hydroxymethyltransferase is located primarily in the mitochondria and cytosol of cells, reflecting its role in cellular metabolism.
2. This enzyme is involved in the reversible interconversion between serine and glycine, which is vital for maintaining amino acid balance in cells.
3. Deficiency or malfunction of serine hydroxymethyltransferase can lead to metabolic disorders due to impaired one-carbon metabolism.
4. The enzyme requires pyridoxal phosphate (vitamin B6) as a cofactor to facilitate its catalytic activity.
5. Serine hydroxymethyltransferase plays a significant role in providing one-carbon units for the synthesis of purines and thymidylate, critical components of DNA.

Review Questions

• How does serine hydroxymethyltransferase contribute to one-carbon metabolism, and why is this process important for cellular functions?
  • Serine hydroxymethyltransferase contributes to one-carbon metabolism by transferring one-carbon units from serine to tetrahydrofolate, forming glycine and 5,10-methylenetetrahydrofolate. This process is vital because it provides the necessary one-carbon units for the synthesis of nucleotides and amino acids, which are essential for DNA replication and overall cellular growth. The enzyme's activity helps maintain metabolic balance and supports various biosynthetic pathways crucial for cell survival.
• Discuss the implications of serine hydroxymethyltransferase dysfunction on amino acid biosynthesis and potential metabolic disorders.
  • Dysfunction of serine hydroxymethyltransferase can disrupt amino acid biosynthesis by impairing the conversion of serine to glycine. This can lead to an imbalance in amino acid levels, resulting in metabolic disorders. Such dysfunction may impact the synthesis of nucleotides and other molecules reliant on one-carbon units, further exacerbating cellular stress and potentially leading to conditions like hyperglycinemia, where elevated glycine levels cause neurological issues.
• Evaluate the importance of serine hydroxymethyltransferase in the context of cancer metabolism and therapeutic approaches.
  • Serine hydroxymethyltransferase has gained attention in cancer research due to its role in supporting rapid cell proliferation through enhanced one-carbon metabolism. Cancer cells often rely on this pathway to generate nucleotides and amino acids necessary for their growth. Targeting this enzyme may offer therapeutic potential by disrupting the metabolic adaptations that allow cancer cells to thrive. By inhibiting serine hydroxymethyltransferase, researchers hope to starve tumors of essential building blocks, providing a novel strategy in cancer treatment.

Related terms

Tetrahydrofolate: A coenzyme derived from folate that serves as a carrier of one-carbon units in various biochemical reactions.

Glycine: The simplest amino acid, acting as a building block for proteins and serving as a substrate in the reactions catalyzed by serine hydroxymethyltransferase.

One-Carbon Metabolism: A collection of biochemical reactions that involve the transfer of one-carbon units for the synthesis of nucleotides, amino acids, and other important molecules.