Essential amino acids, or EAAs, are amino acids that our body needs but cannot produce on its own, and there are 9 of them: Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Aldolase A is made of 350 amino acids, the building blocks of proteins, but the bit that does the work consists of only three of these: lysine, glutamic acid and tyrosine. The rest of the enzyme is packaging.