Sterols oxygenated

P.H.L. Hwang, Inhibitors of protein and RNA synthesis block the cytotoxic effects of oxygenated sterols, Biochim. Biophys. Acta 1136(1992) 5-11. 

Smondyrev, A.M., Berkowit, M.L. 2001. Effects of oxygenated sterol on phospholipids bilayer properties a molecular dynamics simulation. Chem. Phys. Lipids 112, 31-39. 

Oxysterols are reported to act as potent inhibitors of growth in mammalian cell systems because of their interference with sterol biosynthesis (13). Upon superficial examination, brassinosteroids could be regarded as just highly oxygenated sterols. Therefore, two oxysterols (24-ketolanosterol and 7-... 

UH Egli, RA Streuli, E Dubler. Influence of oxygenated sterol compounds on phase transition in model membranes. A study by differential scanning calorimetry. Biochemistry 23 148-152 (1984). 

Now we know the connection runs through an oxygen-sterol. E. R. Nelson et al. 27-Hydroxycholesterol links hypercholesterolemia and breast cancer pathophysiology. 2013. Science 342(6162), p. 1094. DOL 10.1126/science.l241908. 

Cholesta-7,9-dien-3P-ol can be enzymically converted into cholesterol via cholesta-8,14-dien-3P-ol, However, the physiological significance of this observation is uncertain. The intermediary role of a number of oxygenated sterols in the conversion of cholest-7-en-3p-ol into cholesta-5,7-dien-3P-ol by rat liver homogenates has been investigated. 7a,8a-Epoxycholestan-3P-ol, cholestane-3P,7p,8a-triol, cholest-8-ene-3p,7 -diols, cholestane-3p,8a-diol-7-one, and cholest-8(14)-ene-3p,7a-diol, but not cholestane-3p,7a,8a-triol, were efficiently transformed into cholesterol aerobically. However, they are not normal intermediates in cholesterol biosynthesis, since anaerobically they were transformed into cholest-7-en-3P-ol. 

De Riccardis, F., Minale, L., lorizzi, M., Debitus, C., and Levi, C. (1993b) Marine sterols. Side-chain-oxygenated sterols, possibly of abiotic origin, from the New Caledonian sponge Stdodoryx chlorophyUa. J. Nat. Prod., 56, 282-287. 

Iguchi, K., Saitoh, S., and Yamada, Y. (1989) Novel 19-oxygenated sterols from the Okinawan soft coral Litophyton viridis. Chem. Pharm. Butt., 37, 2553-2554. 

Kobayashi, M. and Kanda, F. (1991) Marine sterols. 18. Isolation and structure of fom novel oxygenated sterols from a gorgonian coral Mdithaea ocracea. J. Chem. Soc. Perkin Trans. 1,1177-1179. 

Yang, F., Zhang, H.-J., Uu, Y.-F., Chen, W.-S., and Tang, H.-F. (2009) Oxygenated sterols from marine bryozoan Biftustra grandiceUa. Biochem. Syst. Ecol., 37, 686-689. 

Two types of regulations are important. The diurnal variations in reductase activity are brought about by alterations in the amounts of the enzyme protein and, also, the reductase-specific mRNA. An increase in HMG-CoA reductase appears to be due to an increase in its synthesis while decreases are caused by a cessation of its formation. Several compounds such as oxygenated sterols (but not cholesterol itself) seem to prevent transcription of the reductase gene. Mevalonate (or products of its metabolism), in addition to inhibiting synthesis of the reductase, also appears to enhance its degradation. 

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