Elaboration of lanosterol under enzyme catalysis leads to the core structure of steroids. 14-demethylation of lanosterol by CYP51 eventually yields cholesterol.
Biosynthesis
Description
Illustration
Enzyme
Two molecules of farnesyl pyrophosphate condense with reduction by NADPH to form squalene
squalene synthase
Squalene is oxidized to 2,3-oxidosqualene (squalene epoxide)
squalene monooxygenase
2,3-oxidosqualene is converted to a protosterol cation and finally to lanosterol
E. J. Corey, W. E. Russey, P. R. Ortiz de Montellano (1966). "2,3-Oxidosqualene, an Intermediate in the Biological Synthesis of Sterols from Squalene". Journal of the American Chemical Society88 (20): 4750 - 4751. doi:10.1021/ja00972a056.
I. Abe, M. Rohmer, G. D. Prestwich (1993). "Enzymatic cyclization of squalene and oxidosqualene to sterols and triterpenes". Chemical Reviews93 (6): 2189 - 2206. doi:10.1021/cr00022a009.
A. Eschenmoser, L. Ruzicka, O. Jeger, D. Arigoni (1955). "Zur Kenntnis der Triterpene. 190. Mitteilung. Eine stereochemische Interpretation der biogenetischen Isoprenregel bei den Triterpenen". Helvetica Chimica Acta38 (7): 1890-1904. doi:10.1002/hlca.19550380728.
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