[2] Human β-glucuronidase is a type of glucuronidase (a member of glycosidase Family 2) that catalyzes hydrolysis of β-D-glucuronic acid residues from the non-reducing end of mucopolysaccharides (also referred to as glycosaminoglycans) such as heparan sulfate.

[12][13] This homologous relationship, along with the knowledge that glycosidases often perform hydrolysis catalyzed by two acidic residues, enabled the development of a mechanistic hypothesis.

[14] Using analysis of labeled β-glucuronidase peptides after hydrolysis of a substrate that enters a very stable intermediate stage, researchers have determined that Glu540 is the nucleophilic residue.

However, more recent evidence suggests that these oxocarbenium ion states have lifetimes of 10 femtoseconds - 0.1 nanoseconds (similar to that of a bond vibration period).

[14] Through comparison to the structural data of the homologous enzyme xylanase, it has been suggested that Tyr504 of β-glucuronidase might stabilize the leaving nucleophile (Glu540) or modulate its activity.

[11][17] Deficiencies in β-glucuronidase result in the autosomal recessive inherited metabolic disease known as Sly syndrome or Mucopolysaccharidosis VII.

In addition, mental retardation, short stature, coarse facial features, spinal abnormalities, and enlargement of liver and spleen are observed in surviving patients.