Synthesis and degradation of active sulfate in liver

Abstract

Subcellular distribution patterns of sulfate-activating and 3′-phosphoadenosine 5′phosphosulfate (PAPS)-degrading enzyme activities were studied in rat liver. 1. 1. The activity of sulfate-activating enzyme was found to be highest in the soluble fraction of healthy rat liver. PAPS-degrading enzyme was shown to be lysosomal from the result of the subcellular fractionation study and of the Triton X-100 treatment of whole liver homogenate and lysome. 2. 2. In the process of chronic hepatic damage, the acitivity of sulfate-activating enzyme was increased in the soluble fraction of the liver and decreased thereafter, nearly to the control level. On the other hand, the activity of PAPS-degrading enzyme was gradually elevated in the soluble fraction. 3. 3. The activity of sulfate-activating enzyme was increased significantly in the soluble fraction of the healthy liver with administration of excess vitamin A, whereas the activity was decreased in damaged liver. With excess of vitamin A, the activity of PAPS-degrading enzyme was decreased in the particle fraction, and increased in the soluble fraction of the rat liver both with and without hepatic damage, the change being more marked in the latter.