1. 1. The subcellular distribution of two enzyme systems which degrade 3′-phosphoadenosine 5′-phosphosulfate (PAPS) ("active sulfate") has been determined. PAPS sulfatase has the wider distribution and accounts for most of the PAPS hydrolyzed. The 3′-phosphoadenosine 5′-phosphate (PAP) thus formed might be available to serve as the requisite coenzyme in phenolic sulfotransferase reactions (detoxification). 2. 2. PAPS-phosphatase activity has a more restricted distribution. It is concentrated in the lighter vesicles of the smooth endoplasmic reticulum (Smooth-4 fraction). It is chiefly present in the soluble portion of this fraction. The adenosine 5′-phosphosulfate (APS) thus formed might be available for conversion back to PAPS as required by the needs of the sulfotransferase systems (lipid, mucopolysaccharide, steroid) also localized in the smooth reticulum.
ASJC Scopus subject areas
- Molecular Biology