Mucopolysaccharides in human epidermis.

In a previous publication on the Gram staining material of human epidermis we advanced the theory that keratohyalin contained a highly resistant mucopolysaccharide. In the course of normal keratinization this material was decomposed, while in parakeratotic and many other types of pathologic scales it was retained in the horny layer (1). The evidence presented was indirect: we found that the extent of Grampositivity roughly paralleled the hexosaminet content of hydrolyzed horny layers and mercuric salts which blocked the Gram stain, also greatly reduced the amounts of reactive hexosamine in hydrolyzed scales. We were unable to provide more direct evidence, because this highly resistant substance defied attempts at isolation or selective destruction. In our recent experiments we were able to overcome some of these difficulties. Partial isolation, purification and enzymatic destruction of epidermal mucopolysaccharides will he briefly discussed in this preliminary report.