JBC, Vol. 250, Issue 8, 2789-2794, Apr, 1975
Prostaglandin 9-hydroxydehydrogenase activity in the adult rat kidney. Identification, assay, pathway, and some enzyme properties
C. Pace-Asciak
Prostaglandin F2alpha is converted to 15-keto-13,14-dihydroprostaglandin E2
by adult rat kidney homogenates. A variety of substrates labeled as either
the 9beta position alone or at several other positions in the prostaglandin
molecule were used to define the step at which the crossover from the F
type to the E type prostaglandins takes place. Time course studies further
confirmed that 15-keto-13,14-dihydroprostaglandin F2alpha is the immediate
substrate for this enzyme which we have termed prostaglandin
9-hydroxydehydrogenase. An assay system based on specific loss of tritium
from 9beta-tritiated prostaglandin F2alpha is described. Enzyme activity
with prostaglandin F2alpha as substrate is linear with time up to 10 min,
stimulated by NAD+, saturable at low concentrations of substrate, stable to
storage at minus 25 degrees in phosphate buffer (up to 3 weeks), and has a
broad pH optimum around 7.5. The product,
15-keto,13,14-dihydroprostaglandin E2 was identified by mass spectrometry
through a sodium borohydride-sodium borodeuteride reduction method.