This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Classification and metabolism of amino acids, Subject name: Biochemistry
[{'content': 'All of the following amino acids are one-carbon donors, EXCEPT \nSelect and explain. \nA. Glycine, B. Serine, C. Histidine, D. Threonine', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Sources of one-carbon groups: Serine to glycine (Serine hydroxymethyl transferase reaction) is the primary contributor for methylene THFA. Glycine cleavage system produces methylene groups is the glycine cleavage system Histidine contributes to N5-formimino THFA through FIGLU Tryptophan donates formyl-THFA Choline and betaine are donors of hydroxy methyl groups', 'role': 'assistant'}]