The Inhibition of Testicular Hyaluronidase by Heavy Metals*

The literature on inhibitors of hyaluronidase is both voluminous and contradictory. The contradictions are caused by the differences in methods used, by the differences in enzyme purity, and to a very high degree by the differences in the purity of the substrates used. The latter are often contaminated with protein, with glycogen, and with mucopolysaccharides other than hyaluronic acid, especially when umbilical cord is the source (1). One factor which affects enzyme activity appears to be contamination with heavy metals, especially Fe+++ and Cu++. These metals have a high affinity for some group or groups in the enzyme, causing a reversible inactivation. The most effective reversing agent when Fe+++ is the inactivating metal is pyrophosphate; with Cuff, cysteine appears to be best.