β-Glucuronidase/Arylsulfatase shows a broad specificity for many kinds of β-glucuronides and sulfate esters.
Specificity of β-Glucuronidase:The glycosides that β-D-glucuronic acid forms with a variety of compounds containing hydroxyl groups hydrolyze readily in the presence of β-glucuronidase.
- Such compounds include steroids, such as estriol (Km = 0.42 mM, pH 4.5), androsterone, pregnanediol, tetrahydrocortisone,
- phenols, such as phenolphthalein (Km = 0.39 mM), 4-nitro-phenol, 4-methylumbelliferone,
- drugs such as chloramphenicol and tetrahydrocannabinols,
- and metabolites such as thyroxine and bilirubin.
Polysaccharides that contain β-glucuronic acid residues, such as hyaluronic acid, are also hydrolyzed.
β-Glucuronidase is highly specific for the carbohydrate part: neither α-glucosides nor β-glucosiduronic acids are hydrolyzed. However, the nature of the residue linked to the β-glucuronic acid residue is hardly important at all.
Specific activity
: 5.5 U/ml at +38°C with phenolphthalein-β-glucuronide as the substrate (4.5 U/ml at +25°C with 4-nitro-phenyl-β-D-glucuronide as the substrate = 100,000 Fishman units/ml at +38°C with phenolphthalein-β-glucuronide as the substrate). 1 Fishman unit releases 1 μg phenolphthalein from phenolphthalein-β-glucuronide in 1 hour at +38°C.
Specificity of Acrylsulfatase:Sulfate esters of many phenols are hydrolysed in the presence of arylsulfatase. Examples are steroid sulfates such as estronesulfate, 4-nitrophenyl hydrogen sulfate (K
m = 1.8 mM, pH 7.3), 4-nitro-pyrocatechol 2-sulfate (K
m = 1.25 mM, pH 7.5), and phenolphthalein disulfate.
Specific activity: 2.6 U/ml at +38°C with phenolphthalein disulfate as the substrate (14 U/ml at +25°C with 4-nitrophenyl sulfate as the substrate = 800,000 Roy units/ml at +38°C with 2-hydroxy-5-nitrophenyl sulfate as the substrate). 1 Roy unit releases 1 μg 2-hydroxy-5-nitrophenyl sulfate in 1 hour at +38°C.
Specificity of β-Glucuronidase:The glycosides that β-D-glucuronic acid forms with a variety of compounds containing hydroxyl groups hydrolyze readily in the presence of β-glucuronidase.
- Such compounds include steroids, such as estriol (Km = 0.42 mM, pH 4.5), androsterone, pregnanediol, tetrahydrocortisone,
- phenols, such as phenolphthalein (Km = 0.39 mM), 4-nitro-phenol, 4-methylumbelliferone,
- drugs such as chloramphenicol and tetrahydrocannabinols,
- and metabolites such as thyroxine and bilirubin.
Polysaccharides that contain β-glucuronic acid residues, such as hyaluronic acid, are also hydrolyzed.
β-Glucuronidase is highly specific for the carbohydrate part: neither α-glucosides nor β-glucosiduronic acids are hydrolyzed. However, the nature of the residue linked to the β-glucuronic acid residue is hardly important at all.
Specificity of Acrylsulfatase:Sulfate esters of many phenols are hydrolysed in the presence of arylsulfatase. Examples are steroid sulfates such as estronesulfate, 4-nitrophenyl hydrogen sulfate (K
m = 1.8 mM, pH 7.3), 4-nitro-pyrocatechol 2-sulfate (K
m = 1.25 mM, pH 7.5), and phenolphthalein disulfate.