Objective To examine the SDS-PAGE map and TGase 1 activity in the trimmed nails and epidermal scales of the psoriasis patients.Methods The trimmed nails and epidermal scales were collected respectively from 5 cases of psoriasis patients and 5 healthy volunteers.The SDS-PAGE was performed by the extracted protein from both nails and scales.The TGase 1 activity was detected in the spread scale specimen by using HRP-dansylcadaverine conjugate.Results There were 4 major bands,including 63 kDa,54 kDa,48 kDa and 38 kDa found in the nail or scale SDS-PAGE map from both psoriasis and healthy cases.In comparison of the psoriasis SDS-PAGE map with the healthy cases,the scanning value in most of the 4 major bands was high,P0.05.In the healthy specimen the TGase 1 activity appeared brownish-yellow colored granules localized in the border of the deeper keratinocytes;while the TGase 1 activity was paucity in the psoriasis cases.Conclusion The results of the nail SDS-PAGE and the scale SDS-PAGE were similar in spite of the former with more distinct map,which may be associated with more stability of the protein contained in the nail.The expression level of the major bands in the psoriasis SDS-PAGE was higher than that in the healthy,suggesting the proliferatiing keratinocytes rich in cell products in the psoriasis cases.The TGase 1 activity in paucity suggests that the psoriasis cases may have defective epidermal barrier function.