Purification and properties of prostaglandin 9‐ketoreductase from pig and human kidney

Abstract

Prostaglandin 9-ketoreductase (PG-9-KR) was purified from pig kidney to homogeneity, as judged by SDSjPAGE using an improved procedure. The enzyme is p r o 3 stereoselective with regard to hydrogen transfer from NADPH with prostaglandin E2 as substrate and reduces its 9-keto group with approximately 90% stereoselectivity to form prostaglandin F2.. Approximately 8% of the prostaglandin F formed has the P-configuration. In addition to catalyzing the interconversion of prostaglandin E2 to FZa, PG-9-KR also oxidizes prostaglandin E2, FZa and D2 to their corresponding, biologically inactive, 15-keto metabolites. Incubation of PG-9-KR with prostaglandin F2, and NAD+ leads to the preferential formation of 15-keto prostaglandin FZa rather than prostaglandin E2. This suggests that the prostaglandin E2/prostaglandin Fza ratio is not determined by the NADP' /NADPH redox couple. The enzyme also reduces various other carbonyl compounds (e.g. 9,lO-phenanthrenequinone) with high efficiency. The catalytic properties measured for PG-9-KR suggest that its in vivo function is unlikely to be to catalyze formation of prostaglandin F2,. The monomeric enzyme has a molecular mass of 32 kDa and exists as four isoforms, as judged by isoelectric focusing. PG-9-KR contains 1.9 mol Zn2+/mol enzyme and no other cofactors. Human kidney PG-9-KR was also purified to homogeneity. The human enzyme has a molecular mass of 34 kDa and also exists as four isoforms. Polyclonal antibodies raised against pig kidney PG-9-KR cross-react with human kidney PG-9-KR and also with human brain carbonyl reductase, as demonstrated by Western blot analysis. Sequence data of tryptic peptides from pig kidney PG-9-KR show >90% identity with human placenta carbonyl reductase. From comparison of several properties (catalytical, structural and immunological properties), it is concluded that PG-9-KR and carbonyl reductase are identical enzymes.

Clofibric Acid, a Peroxisome Proliferator-activated Receptor Alpha Ligand, Enhances a Suppressive Effect of Cis-diaminedichloroplatinum on Proliferation of Ovarian Carcinoma Cells

“…CR is a cytoplasmic enzyme expressed in the lung, liver, kidney, and ovary, and its main function is to reduce carbonyl compounds with NADPH (Wermuth, 1981). CR specially promotes conversion of PGE 2 to PGF 2α (Schieber et al 1992). Taken together, the present results suggest that CA could decrease PGE 2 level through induction of CR, resulting in enhancement of antiproliferative effect of CDDP.…”

Carbonyl reductase as a significant predictor of survival and lymph node metastasis in epithelial ovarian cancer

“…CR has been found to be biochemically, immunologically and functionally identical to prostaglandin 9-ketoreductase (PG 9-KR) (Schieber et al, 1992). PG 9-KR oxidises prostaglandin E 2 , F 2α and D 2 to biologically inactive 15-keto metabolites (Schieber et al, 1992).…”

“…PG 9-KR oxidises prostaglandin E 2 , F 2α and D 2 to biologically inactive 15-keto metabolites (Schieber et al, 1992). Prostaglandins play an important role in modulating tumour growth and metastasis in a variety of human tumours (Ablin and Shaw, 1986).…”

Carbonyl Reductase Expression and Its Clinical Significance in Non–Small-Cell Lung Cancer

“…CBR has been found to be identical to prostaglandin 9-ketoreductase, which inactivates prostaglandin E 2 (PGE 2 ) by converting PGE 2 to prostaglandin F 2a (10)(11)(12). PGE 2 , which is produced by cyclooxygenase enzymes, can promote development and progression of malignant tumors (13,14) by promoting angiogenesis through enhancement of vascular endothelial growth factor (VEGF) expression (15,16), inhibition of apoptosis (17), regulation of cytokines (18), and activation of the epidermal growth factor receptor (19).…”