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.
Cytochrome c
Cytochrome c has a primary structure consisting of a chain of about 100 amino acids. Many higher-order organisms possess a chain of 104 amino acids. The sequences of cytochrome c in humans is identical to that of chimpanzees (our closest relatives), but differs more from that of horses.