Studies of phosphorus metabolism by isolated nuclei

摘要: Abstract 1. Isolated rat liver nucleoli catalyze formation of P i with both ribo- and 2-deoxyribonucleoside diphosphates as substrates. Nucleolar GDPase activity is maximal at pH 7.2 to 7.8 40°; it stimulated maximally by magnesium or manganese. The principal products nucleolar are GMP ; no evidence has been obtained for a contribution this polynucleotide phosphorylase. 2. Nucleoli also contain glucose-6-phosphatase inorganic pyrophosphatase. Although such content phosphatases analogous that microsomes, the absence microsomes in isolated nucleoli, non-identity microsomal phosphatases, established several means. 3. results work verify previous histochemical demonstrations nucleoside diphosphatase hepatoma nucleoli.