Lysine is not involved in gluconeogenesis. Gluconeogenesis is the
biosynthesis of new glucose from certain non-carbohydrate carbon substrates like amino acids, etc. Out of the 20 amino acids, 18 are glucogenic (i.e. can be converted to glucose upon gluconeogenesis) while the remaining two amino acids, i.e. lysine and leucine are
purely ketogenic (i.e. can be degraded into acetyl-Co-A).