Studies on diffusing factors: 2. The action of hyaluronidase preparations from various sources upon some substrates other than hyaluronic acid.

The action of enzyme preparations possessing hyaluronidase activity upon a number of substrates other than hyaluronic acid has been studied by Meyer and his colleagues (1940, 1941), by Madinaveitia & Stacey (1944), and by McClean & Hale (1941). The enzymes, for whose purity no claims were made, were prepared from testis, leech, pneumococcus, streptococcus, and Cl. welchii, and the substrates tested included a wide range of natural mucopolysaccharides and glucuronides, and two synthetic ,B-glucosaminides. These studies, which were mainly qualitative, showed that there was a wide variation in the number of substrates which were attacked, depending upon the source of enzyme. Although there is little doubt that in many of these instances enzymes distinct from hyaluronidase were involved, it has been questioned (East, Madinaveitia & Todd, 1941) whether f-glucosaminidase activity is essential to the complete breakdown of hyaluronic acid, and it seemed that this was a point worth resolving.' In the course of repeating, and confirming, some of the experiments of Meyer and his colleagues it was observed that testis enzyme preparations hydrolyzed chondroitin sulphuric acid almost as rapidly as hyaluronic acid, and the kinetics of this action were briefly studied. also in the hope that the enzyme might prove useful in studying the detailed structure of chondroitin sulphuric acid. This particular action of testicular hyaluronidase preparations has been observed independently by Madinaveitia & Stacey (1944), who recorded, however, only the effect on the viscosity of the substrates which they tested.