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Steroidal Triterpenes of Cholesterol Synthesis
Centre for Functional Genomics and Bio-Chips, Faculty of Medicine, Institute of Biochemistry, University of Ljubljana, Zaloška 4, Ljubljana SI-1000, Slovenia
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Received: 18 February 2013; in revised form: 19 March 2013 / Accepted: 27 March 2013 / Published: 4 April 2013
Abstract: Cholesterol synthesis is a ubiquitous and housekeeping metabolic pathway that leads to cholesterol, an essential structural component of mammalian cell membranes, required for proper membrane permeability and fluidity. The last part of the pathway involves steroidal triterpenes with cholestane ring structures. It starts by conversion of acyclic squalene into lanosterol, the first sterol intermediate of the pathway, followed by production of 20 structurally very similar steroidal triterpene molecules in over 11 complex enzyme reactions. Due to the structural similarities of sterol intermediates and the broad substrate specificity of the enzymes involved (especially sterol-Δ24-reductase; DHCR24) the exact sequence of the reactions between lanosterol and cholesterol remains undefined. This article reviews all hitherto known structures of post-squalene steroidal triterpenes of cholesterol synthesis, their biological roles and the enzymes responsible for their synthesis. Furthermore, it summarises kinetic parameters of enzymes (Vmax and Km) and sterol intermediate concentrations from various tissues. Due to the complexity of the post-squalene cholesterol synthesis pathway, future studies will require a comprehensive meta-analysis of the pathway to elucidate the exact reaction sequence in different tissues, physiological or disease conditions. A major reason for the standstill of detailed late cholesterol synthesis research was the lack of several steroidal triterpene standards. We aid to this efforts by summarizing commercial and laboratory standards, referring also to chemical syntheses of meiosis-activating sterols.
Keywords: sterols; steroidal triterpenes; cholesterol synthesis; post-squalene pathway
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MDPI and ACS Style
Ačimovič, J.; Rozman, D. Steroidal Triterpenes of Cholesterol Synthesis. Molecules 2013, 18, 4002-4017.
Ačimovič J, Rozman D. Steroidal Triterpenes of Cholesterol Synthesis. Molecules. 2013; 18(4):4002-4017.
Ačimovič, Jure; Rozman, Damjana. 2013. "Steroidal Triterpenes of Cholesterol Synthesis." Molecules 18, no. 4: 4002-4017.