MIČIČ, D., KARADŽIĆ, V. & RAKIČ, L. Changes of Gamma-aminobutyric Acid, Glutamic Acid and Aspartic Acid in Various Brain Structures of Cats deprived of Paradoxical Sleep. Nature 215 , 169 ...

"In the lab, polyglutamic acid, as a gel, has been found to be able to absorb moisture up to 5,000 times its own weight," says Dr. Li. "But the actual water amount retained depends on the acidity ...