Low-molecular-weight proteinase inhibitor of human epidermis inhibiting papain and trypsin activity

A low-molecular-weight proteinase inhibitor was isolated from human epidermal extracts by means of ultrafiltration, gel filtration and ion-exchange chromatography. On polyacrylamide gel electrophoresis (PAGE), the isolated fraction exhibited a single band of activity at pH 9.4, and inhibitory activity against papain and trypsin was detected in this band. Using sodium-dodecyl-sulphate PAGE, the molecular mass of the inhibitor was estimated to be 2,200 daltons.