Abstract
Ultrastructural localization of β-glycerophosphatase, glucose-6-phosphatase, ATPase and NAD-pyrophosphorylase was investigated in isolated mouse liver nuclei. Activity of β-glycerophosphatase was found in interchromatin granules, in nuclear membranes, perinuclear space and in nuclear pores. Activity of β-glycerophosphatase in the nuclear membranes and in nuclear pores showed a maximum at pH 6.4. Glucose-6-phosphatase activity was detected only in the nuclear membranes and perinuclear space. ATPase activity was demonstrated in nuclear membranes and in RNP-components such as nucleolus, interchromatin granules and coiled bodies and apparently in perichromatin fibrills. NAD-pyrophosphorylase was found in the same RNP-components of the nucleus as ATPase but was absent from the nuclear membranes. A possible physiological role of these enzymes in RNA metabolism is discussed.
