This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Amino Acids Basics, Subject name: Biochemistry
Most important amino-acid substrate for gluconeogenesis - 
Select and explain. 
A. Leucine, B. Lysine, C. Histidine, D. Alanine
D: Alanine
Answer: D: Alanine 
Explanation: Ans. is 'd' i.e., Alanine o The major noncarbohydrate precursors (substrate) for gluconeogenesis are lactate, pyruvate, glycerol, glucogenic amino acids, propionate and intermediates of the citric acid cycle. All aminoacids, exceptfor leucine and lysine, are substrate for gluconeogenesis. Alanine is the most important gluconeogenic amino acid.