Subunit structure of testicular hyaluronidase

Testicular hyaluronidase (hyaluronate glycan hydrolase EC 3.2.1.35), its isolation and characterisation has been reported by several authors [l-6] . However the composition and properties of the preparations described seem strikingly dissimilar. The most obvious explanation that these must have been different molecular forms [7] of the enzyme cannot however fully account for some grave discrepancies observed. Marked variations in the molecular weights [l-3,5,6], two N-terminal amino acids detected in otherwise homogeneous preparation [8], rapid inactivation of the enzyme when in low concentrations and the non-linear dependence of the specific activity on the concentration [9] would rather imply a quaternary structure interpretation than any other. We report in this paper that the molecular form of the enzyme we had isolated and described [7] has a quaternary structure and consists of four subunits with molecular weight of approximately 14,000 each.