Abstract
For the purpose of investigating the site of synthesis of β-glucuronidase, the enzyme was purified, after injection of labeled amino acids, from various cell fractions of regenerating rat liver. Enzyme preparations purified from microsomal, lysosomal, mitochondrial, nuclear and supernatant fractions had identical catalytic and electrophoretic properties. In nonhypoxic rats, incorporation was detectable only in the microsomal enzymes and maximum labeling occurred 30 min after the injection of the labeled amino acid. No label was detectable in the enzyme purified from the lysosomal fraction of nonhypoxic animals. Labeling of enzyme purified from lysosomal fraction was, however, significant after 2 hr of hypoxia.