Amino acids are classified biochemically based on their metabolic fate regarding carbon skeleton disposition into glucose synthesis (glycogenic), fat/ketone body synthesis (ketogenic), or both pathways (mixed). This classification relies on the principle that the remaining carbon skeletons of amino acids, following deamination for nitrogen excretion as urea, serve as precursors for specific energy substrates in mammalian metabolism. Theoretical boundaries exist regarding non-standard residues like selenocysteine and pyrrolysine, which are encoded by stop codons in select organisms but function within distinct enzymatic contexts involving redox reactions or microbial flora rather than standard human protein synthesis pathways.
Amino acids are classified biochemically based on their metabolic fate regarding carbon skeleton disposition into glucose synthesis (glycogenic), fat/ketone body synthesis (ketogenic), or both pathwa…