All are substrates of Gluconeogenesis EXCEPT:

18 amino acids are glucogenic (out of 20). These all can form glucose. Only 2 amino acids are purely ketogenic which cannot form glucose i.e. Leucine, Lysine. As there is controversy regarding Lysine to be purely ketogenic we cannot mark this as not gluconeogenic. Hence its only safe to mark leucine in case one best answer is to marked. Ketogenic Amino Acids Glucogenic And Ketogenic Amino Acids Glucogenic Amino Acid Leucine Lysine(controversial) Tyrosine Tryptophan Threonine Isoleucine Phenyl Alanine Rest all are glucogenic Mostly 3C compounds are good substrates of Gluconeogenesis. Precursors which can be conveed to glucose are: Pyruvate(3C) Lactate(3C) Glycerol(3C) Propionic Acid(3C) Any TCA intermediate Amino Acids Source of pyruvate in Fasting Link Reaction not occurring so pyruvate accumulates lactate from anaerobic glycolysis gets conveed to pyruvate by enzyme lactate Dehydrogenase, which is reversible enzyme Glycerol conves into Glycerol-3-P by Glycerol Kinase in Liver and then Glycerol-3-P forms DHAP (an intermediate of glycolysis) by enzyme Glycerol-3-P dehydrogenase gets conveed to Succinyl CoA, which is intermediate of TCA form glucose as they can form OAA, which can be conveed to glucose