Hydrolyzes high molecular weight hyaluronic acid to produce an intermediate-sized product which is further hydrolyzed by sperm hyaluronidase to give small oligosaccharides. Displays very low levels of activity. Associates with and negatively regulates MST1R. Random hydrolysis of (1->4)-linkages between N-acetyl-beta-D-glucosamine and D-glucuronate residues in hyaluronate. Interacts with MST1R. Widely expressed. No expression detected in adult brain. Belongs to the glycosyl hydrolase 56 family. Was originally thought to be lysosomal. Truncated N-terminus.