Molecular and kinetic properties of 15-hydroxyprostaglandin dehydrogenase (PG-15-HDH) from human placenta.

Some molecular properties of PG-15-HDH from human term placenta were investigated. Using a computer-based weighted linear regression analysis, intersecting initial rate patterns were received for the forward reaction with the prostaglandins (PG) E1, E2, and F2alpha, respectively, and NAD as substrates. NADH exerted a linear competitive inhibition with respect to NAD. The 15-ketoprostaglandins (15-keto-PG) E1 and F2alpha showed a linear noncompetitive inhibition with respect to their corresponding PG. The kinetic patterns suggest an ordered Bi Bi mechanism of PG-15-HDH reaction. The results are discussed with respect to their possible biological significance.