Glutamine
Glutamine is the most abundant naturally occurring, nonessential amino acid in the human body, and one of the few amino acids that can directly cross the blood–brain barrier. Humans obtain glutamine through catabolism of proteins in foods they eat. In states where tissue is being built or repaired, like growth of babies, or healing from wounds or severe illness, glutamine becomes conditionally essential.
Aminoacylase 1 deficiency
Aminoacylase 1 (ACY1: EC 3.5.14) is a zinc binding enzyme which hydrolyzes N-acetyl amino acids into the free amino acid and acetic acid. Of the N-actyl amino hydrolyzing enzymes, aminoacylase 1 is the most common.