Copper sticks to it very tightly, and the copper-bound version is the form most often used in lab and skin-research studies
Jun 2020;19(1):645-660
Relationship between plasma antioxidant concentrations and carotid intima-media thickness: the Asymptomatic Carotid Atherosclerotic Disease In Manfredonia Study
Lpez-Gambero, Cristina Rosell-Valle, Dina Medina-Vera, Juan Antonio Navarro, Antonio Vargas, Patricia Rivera, Carlos Sanjuan, Fernando Rodrguez de Fonseca, Juan Surez International Journal of Molecular Sciences.2021
Its exceptional structural stability, retained activity in gastric juice for over 24 hours, tolerance across pH 1-11, derives from its high proline content and absence of cleavage-prone motifs in the 15-residue sequence