Β-Methylamino-L-alanine

3-Methylamino-L-alanine

Β-Methylamino-L-alanine (BMAA) is a non-proteinogenic amino acid with the chemical formula C₄H₁₀N₂O₂. It is produced by certain species of cyanobacteria, also known as blue-green algae. BMAA has been implicated in various neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), Alzheimer's disease, and Parkinson's disease.

Discovery and Sources

BMAA was first discovered in 1967 in the seeds of the cycad plant, which are used as a food source in some cultures. It has since been found in various aquatic environments, particularly in association with cyanobacterial blooms. Cyanobacteria are known to produce BMAA, which can accumulate in the food web, affecting organisms that consume contaminated water or food.

Chemical Structure and Properties

BMAA is structurally similar to the amino acid alanine, with a methylamino group attached to the beta carbon. This structural similarity allows BMAA to be mistakenly incorporated into proteins in place of alanine, potentially leading to protein misfolding and aggregation, which are hallmarks of several neurodegenerative diseases.

Mechanism of Toxicity

The exact mechanism by which BMAA exerts its neurotoxic effects is not fully understood. However, several hypotheses have been proposed:

• **Excitotoxicity**: BMAA may act as an excitotoxin, overstimulating glutamate receptors and leading to neuronal damage.
• **Protein Misincorporation**: BMAA can be mistakenly incorporated into proteins, leading to misfolded proteins and cellular stress.
• **Oxidative Stress**: BMAA may induce oxidative stress, damaging cellular components and leading to cell death.

Health Implications

Exposure to BMAA has been linked to an increased risk of developing neurodegenerative diseases. Studies have shown that populations with high exposure to BMAA, such as those consuming cycad seeds or living near cyanobacterial blooms, have higher incidences of ALS and other neurodegenerative conditions.

Environmental Impact

Cyanobacterial blooms, which produce BMAA, are becoming more frequent due to factors such as climate change and nutrient pollution. These blooms can contaminate water supplies and aquatic food sources, posing a risk to both human and animal health.

Research and Controversies

Research on BMAA is ongoing, with scientists investigating its role in neurodegenerative diseases and its presence in the environment. There is some controversy regarding the extent of BMAA's impact on human health, with some studies suggesting a strong link to neurodegenerative diseases, while others find no significant association.

See Also

• Amino acid
• Cyanobacteria
• Neurodegenerative disease
• Amyotrophic lateral sclerosis
• Alzheimer's disease
• Parkinson's disease
• Excitotoxicity
• Oxidative stress