Studies of beta-glucuronidase in first-trimester placenta, term placenta and hydatidiform mole

The specific activity and isoenzyme pattern of beta-glucuronidase (beta-D-glucuronide glucurononosohydrolase, EC 3.2.1.31) from first-trimester placenta, term placenta and hydatidiform mole were compared. Enzyme activity is highest in term placenta and lowest in hydatidiform mole, reflecting the steroid conjugation requirements of the tissues. The difference in enzyme activity is due to variation in the level of one isoenzyme form (isoenzyme B) of beta-glucuronidase, which is absent in molar tissue. The possible cause for the changing isoenzyme pattern is discussed.