HUMAN PLACENTAL AMINO ACID NAPHTHYLAMIDASES - THEIR MOLECULAR INTERRELATIONS AND CORRELATIONS WITH PERINATAL FACTORS

Variations in the human placental naphthylamidases were studied in a series of 1000 consecutive births from the University Hospital, Uppsala, Sweden. Four main components can be distinguished by starch gel electrophoresis at pi I 8.2. They arc called A, B, C and I) in decreasing order of mobility toward the anode and they differ with respect to substrate specificity, inhibition by L-methionine and molecular weight. The C and D components are restricted to the placenta, while the A and B enzymes may occur also in other organs. No electrophoretic polymorphism was detected in the four molecular forms of naphtliylamidasc. The levels of the A and 13 enzymes showed some seasonal variations. Correlations between the activities of the different naphthylamidases may be explained on the basis of common peptide subunits or coordinate synthesis. Significant associations were found between enzyme A and abortion history, enzyme 13 and gestation length and enzyme C and birth weight. © 1969 S. Karger AG, Basel.