Cholinesterases in human skin.

This study concerns the distribution of cholinesterases in human skin. Previous work on this subject was published last year by Hurley, Shelley and Koelle (1) These authors used a method originated by Koelle (2, 3). In Koelle's method, acetyithiocholine and butyryithiocholine are used as substrates. It is assumed that acetyithiocholine is split by specific acetyicholinesterase as well as by nonspecific cholinesterase; butyryithiocholine on the other hand is not split by specific acetyicholinesterase but is attacked only by non-specific cholinesterase. In Koelle's procedure any free thiocholine liberated in the section by enzymatic action from the thiocholine ester is precipitated locally as dupric thiocholine. On addition of ammonium sulfide the copper of cupric thiocholine transforms into brown insoluble cupric sulfide. This brown precipitate serves to mark the sites of cholinesterase activity. With this method Hurley, et al. (1) found specific cholinesterase activity around human eccrine glands. In my work, Gomori's (4) modification of Koelle's method was used.