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Cholesterol total synthesis in chemistry describes the total synthesis of the complex biomolecule cholesterol and is considered a great scientific achievement. [1] The research group of Robert Robinson with John Cornforth ( Oxford University ) published their synthesis in 1951 [ 2 ] and that of Robert Burns Woodward with Franz Sondheimer ...
The first step is synthesizing the backbone (sphingosine or glycerol), the second step is the addition of fatty acids to the backbone to make phosphatidic acid. Phosphatidic acid is further modified with the attachment of different hydrophilic head groups to the backbone. Membrane lipid biosynthesis occurs in the endoplasmic reticulum membrane ...
Cholesterol is the principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils. [3] [4]Cholesterol is biosynthesized by all animal cells [citation needed] and is an essential structural and signaling component of animal cell membranes.
Overview of cholesterol biosynthesis. Lanosterol is a precursor to cholesterol. This final conversion occurs in many steps. Mechanistically, the enzyme oxidosqualene:lanosterol cyclase catalyzes the formation of four rings along the long chain of the substrate (oxidosqualene), producing lanosterol.
These involve 2 hydroxylations of the cholesterol side-chain, which generate, first, 22R-hydroxycholesterol and then 20alpha,22R-dihydroxycholesterol. The final step cleaves the bond between carbons 20 and 22, resulting in the production of pregnenolone and isocaproic aldehyde. Each monooxygenase step requires 2 electrons (reducing equivalents).
It is a cytochrome P450 enzyme, which belongs to the oxidoreductase class, and converts cholesterol to 7-alpha-hydroxycholesterol, the first and rate limiting step in bile acid synthesis. The inhibition of cholesterol 7-alpha-hydroxylase (CYP7A1) represses bile acid biosynthesis.
HMG-CoA reductase (3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, official symbol HMGCR) is the rate-controlling enzyme (NADH-dependent, EC 1.1.1.88; NADPH-dependent, EC 1.1.1.34) of the mevalonate pathway, the metabolic pathway that produces cholesterol and other isoprenoids.
Lanosterol is a key four-ringed intermediate in cholesterol biosynthesis. [6] [7] In humans, lanosterol synthase is encoded by the LSS gene. [8] [9] In eukaryotes, lanosterol synthase is an integral monotopic protein associated with the cytosolic side of the endoplasmic reticulum. [10]