Open AccessProperties of Prostaglandin Synthetase of Rabbit Kidney Medulla
Author(s) -
SCHWARTZMAN Michal,
GAFNI Yedidya,
RAZ Amiram
Publication year - 1976
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1976.tb10332.x
Subject(s) - arachidonic acid , microsome , prostaglandin , prostaglandin f2alpha , chemistry , biosynthesis , renal medulla , stimulation , medicine , endocrinology , kidney , prostaglandin e , albumin , biochemistry , glutathione , biology , in vitro , enzyme
The formation in vitro of prostaglandins E 2 , D 2 and F 2α from arachidonic acid by rabbit kidney medulla homogenate or microsomal fraction is markedly affected by the composition of the incubation medium employed. Optimal biosynthesis is obtained in 0.1 M potassium phosphate buffer, with the optimum pH being 8.0–8.8. Under these conditions prostaglandin formation is linear up to arachidonic acid concentration of 30 μM. The initial rate of formation of prostaglandin E 2 + prostaglandin D 2 is 3–4 times higher than that of prostaglandin F 2α . Reduced glutathione (1 mM) did not affect the biosynthesis by medulla homogenate and produced only small stimulation of the biosynthesis by microsomal powder. Hydroquinone produced a small stimulation at a low concentration of 0.005 mM, and a strong inhibition at concentrations of 0.1 mM or higher. Addition of bovine serum albumin (0.1%) reduced the microsomal biosynthesis of prostaglandins by approximately 80%. Addition of boiled homogenate or boiled 140000 × g supernatant produced small stimulation of microsomal biosynthesis while 140000 × g supernatant (not boiled) caused small inhibition which was not dose‐related. It appears that rabbit kidney prostaglandin‐synthetase converts arachidonic acid to prostaglandins E 2 and F 2α in comparable amounts, without apparent need for a cytoplasmic soluble cofactor or specific reducing agents.