why methionine is starting amino acids

Answer 1

Methionine is considered a starting amino acid because it acts as the initiator for protein synthesis in many organisms, including humans. It is the first amino acid incorporated into the growing peptide chain during translation in the ribosome.

One reason for this is that methionine has a special codon, AUG, which serves as the start codon for protein synthesis. The start codon signals the ribosome to begin translation and allows it to recognize the correct reading frame for mRNA.

Additionally, methionine is involved in various important cellular processes, such as protein synthesis, metabolism, and detoxification. It plays a crucial role in the initiation of translation and is necessary for proper protein folding and function.

Methionine is also an essential amino acid, meaning it cannot be synthesized by the body and needs to be obtained from dietary sources. Therefore, ensuring that methionine is available at the beginning of protein synthesis helps to ensure the proper assembly of proteins in the cell.