A small proportion of the protein of stratum corneum of human epidermal callus is insoluble
even when boiled in solutions containing sodium dodecylsulfate and a reducing agent. This
protein is present in the cornified envelope, a structure located beneath the plasma
membrane. When cornified envelopes were dissolved by exhaustive proteolytic digestion
and the products analyzed by chromatography, approximately 18% of the total lysine
residues were found as the cross-linking dipeptide+(y-glutamyl) lysine. Labeled cornified …

The cornified envelope of terminally differentiated human epidermal keratinocytes consists
of cross-linked protein | CiNii Research … The cornified envelope of terminally
differentiated human epidermal keratinocytes consists of cross-linked protein …