Purification and properties of hyaluronidase from human liver. Differences from and similarities to the testicular enzyme

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Abstract
Human liver hyaluronidase was purified to homogeneity by (NH4)2SO4 fractionation, chromatography on hydroxyapatite and DEAE-cellulose, and preparative disc polyacrylamide-gel electrophoresis. The enzyme had a pH optimum of 3.8-4.0, a molecular weight (determined by gel filtration) of 76000, and a Km of 0.05 mg/ml for purified human umbilical-cord hyaluronic acid. It generally resembled hyaluronidases studied in other tissues which are believed to be lysosomal, but shared a number of characteristics with a partially purified bovine testicular hyaluronidase. Neither enzyme exhibited inhibition by high concentrations of substrate, but both were competitively inhibited by dermatan sulphate and keratan sulphate. Both enzymes exhibited increased activity in the presence of albumin, probably owing to an increased susceptibility of substrate to enzyme action. The liver enzyme was inhibited by NaCl, but the testicular enzyme exhibited an increase in activity in the presence of the salt which was similar to the effect observed with albumin. The different response toward Cl- ion appeared to be the most significant difference between the two enzymes.