Purification and Characterization of Glutathione-Independent Denitration Enzyme of Organic Nitrate Esters in Rabbit Hepatic Cytosol

• Published in: Biological & pharmaceutical bulletin Vol. 18; no. 10; pp. 1352 - 1355
• Main Authors: FUKUSHIMA, Kiyomi, SATOH, Tetsuo, HIROSE, Takuya, TSUKAMOTO, Mayumi, OGAWA, Naoyoshi, SUWA, Toshio
• Format: Journal Article
• Language: English
• Published: Tokyo The Pharmaceutical Society of Japan 1995; Maruzen; Japan Science and Technology Agency
• Subjects: Ammonium Sulfate; Animals; Biological and medical sciences; Chromatography, Gel; Chromatography, Ion Exchange; Cytochrome P-450 Enzyme System - metabolism; Cytosol - enzymology; Electrophoresis, Polyacrylamide Gel; Enzymes. Coenzymes. Vitamins. Pigments; Fundamental and applied biological sciences. Psychology; glutathione-independent denitration; Hydrogen-Ion Concentration; In Vitro Techniques; Liver - enzymology; Metabolisms and neurohumoral controls; Molecular Weight; Nitrates - metabolism; organic nitrate ester; Proteins - metabolism; rabbit hepatic cytosol; Rabbits; Substrate Specificity; Transferases - chemistry; Transferases - isolation & purification; Transferases - metabolism; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Antianginal agent; Purification; Enzyme; Liver; Rabbit; Lagomorpha; Metabolism; Cytosol; Characterization; Ester; Vertebrata; Mammalia; Animal; Organic nitrate; Denitration
• ISSN: 0918-6158; 1347-5215
• DOI: 10.1248/bpb.18.1352

The enzyme responsible for glutathione (GSH)-independent denitration of organic nitrate esters was purified by gel chromatography, ion-exchange chromatography and affinity chromatography from rabbit hepatic cytosol. The enzyme showed a molecular mass of 175kDa and consisted of three subunits of 59kDa. The enzyme exerted its maximum activities at around pH 9, when isosorbide dinitrate (ISDN) was used as substrate. The enzyme possessed a low Km value (10-6M) for various organic nitrate esters. The present enzyme is likely to be involved in the denitration of organic nitrate esters in conjunction with known enzymes, GSH S-transferase (GST) and cytochrome P450.