protein methyltransferase activity

Definition

Target type: molecularfunction

Catalysis of the transfer of a methyl group (CH3-) to a protein. [GOC:jl]

Protein methyltransferases (PMTs) are a diverse group of enzymes that catalyze the transfer of a methyl group from a donor molecule, typically S-adenosyl methionine (SAM), to a specific amino acid residue within a target protein. This process is known as methylation. The molecular function of PMTs involves a series of steps:

1. **Substrate Binding:** PMTs first bind to their target protein and the methyl donor SAM. The specific amino acid residue that will be methylated is located within a specific recognition motif on the target protein.

2. **SAM Binding and Activation:** SAM binds to the active site of the PMT and is activated through interactions with conserved amino acid residues within the enzyme.

3. **Methyl Group Transfer:** The activated methyl group from SAM is then transferred to the target amino acid residue, typically lysine, arginine, or histidine. This transfer reaction is highly specific and is dictated by the structure of the active site and the surrounding residues.

4. **Product Release:** After the methylation reaction, the methylated protein and S-adenosyl homocysteine (SAH), the demethylated form of SAM, are released from the enzyme.

5. **Regulation:** The activity of PMTs is often tightly regulated by a variety of factors, including the availability of SAM, the presence of inhibitors, and the phosphorylation state of the enzyme.

The methylation of proteins by PMTs plays a crucial role in a wide range of cellular processes, including:

* **Gene expression:** Methylation of histones, proteins that package DNA, can alter chromatin structure and regulate gene transcription.
* **Signal transduction:** Methylation of signaling proteins can modify their activity and alter the flow of information within cells.
* **Protein stability:** Methylation can affect the stability and degradation of proteins.
* **Cellular metabolism:** Methylation can modulate the activity of enzymes involved in various metabolic pathways.
* **Immune response:** Methylation plays a role in regulating immune cell development and function.

Dysregulation of PMT activity has been implicated in various diseases, including cancer, neurodevelopmental disorders, and autoimmune diseases. The study of PMTs and their role in methylation is a rapidly growing field with significant implications for our understanding of cellular processes and disease development.'
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Proteins (5)

Compounds (22)