Enzymatic Properties of Squalene Epoxidase from Saccharomyces cerevisiae

• Published in: Biological & pharmaceutical bulletin Vol. 16; no. 4; pp. 349 - 352
• Main Authors: SATOH, Toshihiko, HORIE, Masahiro, WATANABE, Hisako, TSUCHIYA, Yoshimi, KAMEI, Toshio
• Format: Journal Article
• Language: English
• Published: Tokyo The Pharmaceutical Society of Japan 01.04.1993; Maruzen; Japan Science and Technology Agency
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Benzylamines - pharmacology; Biological and medical sciences; Candida albicans - enzymology; Enzyme Inhibitors - pharmacology; Enzymes and enzyme inhibitors; Flavin-Adenine Dinucleotide - metabolism; Fundamental and applied biological sciences. Psychology; Fungal Proteins - metabolism; Hydrogen-Ion Concentration; Kinetics; Microsomes - enzymology; NADP - metabolism; Naphthalenes - pharmacology; NB-598; Octoxynol; Oxidoreductases; Oxygenases - antagonists & inhibitors; Oxygenases - metabolism; Polyethylene Glycols - pharmacology; Rats; Saccharomyces cerevisiae; Saccharomyces cerevisiae - enzymology; Species Specificity; squalene epoxidase; squalene epoxidase inhbitor; Squalene Monooxygenase; Terbinafine; Thiophenes - pharmacology; Fungi; Squalene monooxygenase (2,3-epoxidizing); Enzymatic activity; Microbial origin; Enzyme; Ascomycetes; Species specificity; Kinetic parameter; Saccharomyces cerevisiae; Thallophyta
• ISSN: 0918-6158; 1347-5215
• DOI: 10.1248/bpb.16.349

Squalene epoxidase is a microsomal membrane-associated enzyme that acts as an important regulator in the sterol biosynthetic pathway. In this study, the enzymatic properties of squalene epoxidase from Saccharomyces cerevisiae were examined. Unlike Candida squalene epoxidase, S. cerevisiae squalene epoxidase required NADPH for enzyme reaction. However, S. cerevisiae enzyme reaction did not require FAD or autologous S105 fraction. Unlike rat squalene epoxidase, the activity of S. cerevisiae was reduced by Triton X-100, a nonionic detergent. Terbinafine, an inhibitor of fungal squalene epoxidase, inhibited the enzyme in a non-competitive manner, while NB-598, an inhibitor of mammalian squalene epoxidase, barely inhibited it in a partially non-competitive manner. Thus, the properties of squalene epoxidase from S. cerevisiae were different from those of squalene epoxidase from rats and Candida, which were previously known. We propose that a species difference of squalene epoxidase exists not only between animals and fungi but between Candida and Saccharomyces.