Comparative studies of rodent anionic arylsulfatases.

Area of Science:

• Biochemistry
• Enzymology
• Comparative Physiology

Background:

• Hepatic arylsulfatase activity is crucial for cellular metabolism.
• Previous studies have not fully characterized rodent hepatic arylsulfatases.

Purpose of the Study:

• To characterize murine and rat hepatic arylsulfatase activities.
• To differentiate between arylsulfatase A and B in rodent liver.

Main Methods:

• DEAE-ion exchange chromatography was used to separate enzyme fractions.
• Enzyme kinetics, thermostability, and substrate specificity were analyzed.
• Immunological similarity to arylsulfatase B was assessed.

Main Results:

• A significant portion of hepatic arylsulfatase activity in mice and rats eluted under high salt conditions.
• This fraction contained arylsulfatase A and an enzyme immunologically similar to arylsulfatase B.
• Anionic arylsulfatase B exhibited thermostability, silver resistance, phosphate inhibition, linear kinetics, and a higher pH optimum than arylsulfatase A.
• Anionic arylsulfatase B hydrolyzed chondroitin-4-SO4 heptasaccharide and resolved into 55 and 115 kd fractions via Sephacryl S-300 gel filtration.
• Rodent arylsulfatase A activity was underestimated using 4-methyl-umbelliferyl sulfate as a substrate.

Conclusions:

• Rodent liver contains distinct anionic arylsulfatase B with unique biochemical properties.
• The characterization of these enzymes is essential for understanding their physiological roles.
• Standard assays may underestimate rodent arylsulfatase A activity.