We performed Proteomics on the isolated stratum corneum from adult frog skin, hindlimb toes without claws, and hindlimb toes which bear cornified claws. We aimed to identify yet undescribed genes relevant for cornification which are arranged in a cluster which we named Amphibian Epidermal Differentiation Cluster (AEDC). We needed to use the protease GludC instead of Trypsin in order to obtain detectable peptides.