Methionine is an essential amino acid that is crucial for the health of humans and animals. It cannot be synthesized by the body and must be obtained through dietary intake. Here is some basic information about methionine:

### Biological Functions

- **Protein Synthesis**: As one of the 20 standard amino acids, methionine plays a role in the construction of proteins.

- **Methyl Donor**: Methionine is an important methyl donor in the body, participating in various biochemical reactions, including the methylation of DNA, RNA, and proteins.

- **Antioxidant Role**: It contributes to the formation of glutathione, a powerful antioxidant that protects cells from free radical damage.

- **Detoxification**: In the liver, methionine aids in converting harmful substances into forms that are easier to excrete.

### Food Sources

Methionine is primarily found in high-protein foods, including but not limited to:

- **Animal Products**: Meat, fish, poultry, eggs, and dairy products.

- **Plant-Based Foods**: While present in lower amounts, it can also be found in some nuts, seeds, legumes, and grains.

### Industrial Applications

- **Feed Additive**: Due to its importance for animal growth, methionine is widely used as a nutritional supplement in poultry, swine, and other livestock feeds.

- **Food Fortification**: It is sometimes added to certain foods to enhance their nutritional value.

- **Pharmaceutical Industry**: Methionine is used in the manufacture of medications or as a component in supportive therapies.