Studies on the chaotropically solubilized arylsulfatase C and estrone sulfatase of sheep brain

Abstract

Arylsulfatase C (aryl-sulfate sulfohydrolase, EC 3.1.6.1) from sheep brain acetone powder was solubilized with the chaotropic agent, KSCN. Antichaotropes such as (NH₄)₂SO₄ or sodium citrate significantly enhanced the activity of the solubilized enzyme indicating that hydrophobicity was an important factor influencing the enzyme activity. Dialysis or gel filtration of the solubilized enzyme resulted in a marked loss of activity. A dialyzable activator could reconstitute the activity in the presence of the antichaotropes. The activator was purified partially and preliminary studies indicated it to be a low molecular weight peptide. Arylsulfatase C and estrone sulfatase activities were compared in the solubilized enzyme. Estrone sulfatase activity was also increased in the presence of antichoatropes at lower concentration in comparison to arylsulfatase C. It however did not show a requirement for the dialyzable activator. Kinetic studies showed that elevation of enzyme activity by the antichaotropes and activator in the case of arylsulfatase C and by antichaotropes in the case of estrone sulfatase was due to an increase in V with a decrease K_m.