Chemistry:Lathosterol
Lathosterol is a cholesterol-like molecule found small amounts in humans.[1] The enzyme Δ7-sterol 5(6)-desaturase converts it to 7-dehydrocholesterol. It is accumulated in lathosterolosis.[2]
Biosynthesis
The final step in the biosynthesis of lathosterol is by reduction of the double bond in the sidechain of the sterol 5α-cholesta-7,24-dien-3β-ol when acted on by the enzyme Δ24-sterol reductase, which uses nicotinamide adenine dinucleotide phosphate (NADPH) as its cofactor.[3][4]
In cholesterol biosynthesis
In vertebrates, lathosterol is an intermediate in the pathway to cholesterol via 7-dehydrocholesterol.[5][6][7] The enzyme Δ7-sterol 5(6)-desaturase catalyses the oxidation reaction:
It uses two molecules of the cofactor ferrocytochrome b5 with two protons and one oxygen for each molecule of lathosterol converted.[5]
See also
References
- ↑ Myant N.M. (1981). "The Distribution of Sterols and Related Steroids in Nature". The Biology of Cholesterol and Related Steroids: 123–159. doi:10.1016/B978-0-433-22880-6.50010-2. ISBN 9780433228806.
- ↑ Ho, A. C. C.; Fung, C. W.; Siu, T. S.; Ma, O. C. K.; Lam, C. W.; Tam, S.; Wong, V. C. N. (2013). "Lathosterolosis: A Disorder of Cholesterol Biosynthesis Resembling Smith-Lemli-Opitz Syndrome". JIMD Reports - Volume 12. 12. pp. 129–134. doi:10.1007/8904_2013_255. ISBN 978-3-319-03460-7.
- ↑ Enzyme 1.3.1.72 at KEGG Pathway Database.
- ↑ "Cholesterol biosynthesis from lanosterol: development of a novel assay method and characterization of rat liver microsomal lanosterol delta 24-reductase". Biochem. J. 326 (2): 609–16. 1997. doi:10.1042/bj3260609. PMID 9291139.
- ↑ 5.0 5.1 Enzyme 1.14.19.20 at KEGG Pathway Database.
- ↑ "The Intermediary Role of Δ5,7-cholestadien-3-β-ol in Cholesterol Biosynthesis". J. Biol. Chem. 239: 1381–7. 1964. doi:10.1016/S0021-9258(18)91325-6. PMID 14189869.
- ↑ "Temperature-induced differential kinetic properties between an initial burst and the following steady state in membrane-bound enzymes: studies on lathosterol 5-desaturase". Arch. Biochem. Biophys. 339 (2): 298–304. 1997. doi:10.1006/abbi.1996.9871. PMID 9056262.
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