How many common amino acids are proteins typically composed of?

Proteins are typically composed of 20 common amino acids, which serve as the building blocks for protein synthesis in living organisms. These amino acids are encoded by the genetic code and play crucial roles in the structure and function of proteins. Each amino acid has a unique side chain that determines its characteristics and interaction with other amino acids, influencing the overall shape and function of the protein.

The collective properties of these 20 amino acids allow organisms to produce a vast array of proteins, each with specific functions necessary for life, such as enzymes, hormones, and structural components. The number 20 is well-established in biochemistry, reflecting those standard amino acids involved in protein synthesis rather than any additional or modified forms that may occur in specific contexts or organisms.