This paper describes the use of both mammalian and bacterial expressio
n systems as tools to study the structural and functional relationship
s of proteins encoded by cDNAs to both rat and human aryl sulfotransfe
rases. In particular, we describe the use of the mammalian COS cell sy
stem for functional expression studies, and the use of Escherichia col
i for the expression and purification of a sulfotransferase fusion pro
tein suitable as an antigen for the generation of sulfotransferase ant
ibodies.