MUCINASE: A BACTERIAL ENZYME WHICH HYDRO- LYZES SinvOVIAL FLUID MUCIN AND OTHER MUCINS*

In the course of a series of investigations undertaken in this laboratory to obtain as complete a knowledge as possible of the physiology of normal and pathological joints, investigations concerning the metabolism of ‘synovial fluid mucin were undertaken. The two possible mechanisms for removal of mucin from the joint appear to be enzymatic destruction within the joint or removal by way of the lymphatics. In view of the known difficulty in removing globulin (a smaller molecule than mucin) from the joint (l), it seemed probable that enzymatic activity was the important factor. In an attempt to obtain evidence of the presence in normal or pathological fluid of an enzyme capable of destroying mucin, specimens of sterile normal and pathological fluids were allowed to stand for varying periods of time at 25’ and 37”. In no instance was any decrease in mucin noted nor did any change in mucin occur. However, in the course of other studies on synovial fluid mucin, a specimen of normal synovial fluid was encountered which had lost its viscosity and from which mucin could no longer be precipitated as a ropy mass by the addition of dilute acetic acid. The possibility that the mucin had been destroyed by an enzyme,