Urea-extractable protein from human epidermis.

The major protein fraction extracted from human epidermis by urea has the following characteristics: 1.(1) A molecular weight of approximately 600 000.2.(2) A copper content of 0.03% giving a minimum molecular weight of 212 000.3.(3) A non-protein moiety indicated by1.(a) protein/dry weight ratio2.(b) anomalous ultraviolet absorption spectrum3.(c) high-voltage electrophoresis after mild alkaline or acid treatment4.(d) an excess of imidazole groups by Pauly reaction compared with the number of histidine residues by amino acid analysis.