Aryl sulfotransferase in rat liver: multiplicity and substrate specificity

Area of Science:

• Biochemistry
• Enzymology
• Molecular Biology

Background:

• Aryl sulfotransferase enzymes play a crucial role in the sulfation of various compounds.
• Understanding the multiplicity and characteristics of these enzymes is essential for comprehending their biological functions.
• Previous studies indicated the presence of sulfation activity in rat liver cytosol.

Purpose of the Study:

• To purify and characterize aryl sulfotransferase from rat liver.
• To investigate the substrate specificity and multiplicity of the purified enzyme fractions.
• To compare the properties of rat liver aryl sulfotransferase with those found in other species.

Main Methods:

• Purification of rat liver aryl sulfotransferase using diethylaminoethyl-cellulose or chromatofocusing chromatography.
• Assay of sulfation activity using various substrates, including p-nitrophenol (PNP) and beta-naphthol.
• Analysis of substrate specificity across different purified fractions.

Main Results:

• Three distinct fractions (I, II, and IV) with sulfation activity were obtained.
• Fraction IV showed activity with tyramine and low-concentration PNP, consistent with the M enzyme.
• Substrate specificity varied among the fractions, with PNP and beta-naphthol being common substrates for all three.

Conclusions:

• Rat liver aryl sulfotransferase exhibits multiplicity, with distinct fractions possessing different substrate specificities.
• The observed multiplicity differs from that of human platelet aryl sulfotransferase, suggesting species-specific variations.
• Further research is needed to fully elucidate the functional significance of these enzyme differences across tissues and species.