The body regulates the synthesis of non-essential amino acids in the process of amino acid metabolism through several mechanisms, including feedback inhibition, substrate availability, and hormonal control. These mechanisms ensure that the body maintains a proper balance of amino acids for protein synthesis and other metabolic processes.1. Feedback inhibition: This is the primary mechanism for regulating the synthesis of non-essential amino acids. In this process, the end product of a metabolic pathway inhibits the activity of the first enzyme in the pathway, effectively slowing down or stopping the production of that amino acid. For example, when the concentration of a specific non-essential amino acid is high, it will inhibit the enzyme responsible for its synthesis, preventing the production of more of that amino acid until its levels decrease.2. Substrate availability: The availability of precursor molecules and substrates also plays a role in regulating the synthesis of non-essential amino acids. If the precursor molecules required for the synthesis of a particular amino acid are not available, the synthesis of that amino acid will be limited. For example, the synthesis of the non-essential amino acid alanine requires pyruvate as a precursor. If pyruvate levels are low, alanine synthesis will be limited.3. Hormonal control: Hormones can also influence the synthesis of non-essential amino acids. For example, insulin promotes the uptake of amino acids by cells and stimulates protein synthesis, while glucagon has the opposite effect, promoting protein breakdown and the release of amino acids into the bloodstream. These hormonal signals help to regulate the overall balance of amino acids in the body.In summary, the body regulates the synthesis of non-essential amino acids through feedback inhibition, substrate availability, and hormonal control to maintain a proper balance of amino acids for various metabolic processes.