Ellie Whitney

“releases amino acids.* These amino acids mix with amino acids from
dietary protein to form an “amino acid pool” within the cells and circulating
blood. The rate of protein degradation and the amount of protein intake may vary,
but the pattern of amino acids within the pool remains fairly constant. Regardless
of their source, any of these amino acids can be used to make body proteins or
other nitrogen-containing compounds, or they can be stripped of their nitrogen
and used for energy (either immediately or stored as fat for later use).
nitrogen Balance Protein turnover and nitrogen balance go hand”
― Eleanor Whitney, Understanding Nutrition