Question

mammals, all alpha amino acids
except lysine and threonine can be transmitted why​

Answer 1

Answer:

Because for two substances to undergo a transamination reaction one must be an alpha amino acid, which Lysine is (it also contains a free amino group in its side chain). Proline is not an alpha keto acid, it is an amino acid which comprises its alpha amino group in a cyclic form (it is a pyrrolidine ring).

Answer 2

Answer:

What is the fate of amino acids released on protein digestion or turnover? Any not needed as building blocks are degraded to specific compounds. The major site of amino acid degradation in mammals is the liver. The amino group must be removed, inasmuch as there are no nitrogenous compounds in energy-transduction pathways. The α-ketoacids that result from the deamination of amino acids are metabolized so that the carbon skeletons can enter the metabolic mainstream as precursors to glucose or citric acid cycle intermediates. The fate of the α-amino group will be considered first, followed by that of the carbon skeleton