Biosynthesis of cholesterol: Difference between revisions
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<StructureSection load='' size='350' side='right' scene='HMG-CoA_Reductase/1dq8_starting_scene/1' caption='Crystal Structure of HMG-CoA, (PDB code [[1dq8]])'> | <StructureSection load='' size='350' side='right' scene='HMG-CoA_Reductase/1dq8_starting_scene/1' caption='Crystal Structure of HMG-CoA, (PDB code [[1dq8]])'> | ||
Synthesis within the body starts with the mevalonate pathway where two molecules of <scene name='43/430893/Cv/2'>acetyl-CoA</scene> condense to form <scene name='92/929923/Cv/1'>acetoacetyl-CoA</scene>. This is followed by a second condensation between acetyl CoA and acetoacetyl-CoA to form <scene name='92/929923/Cv/2'>3-hydroxy-3-methylglutaryl CoA (HMG-CoA)</scene>. This molecule is then reduced to <scene name='92/929923/Cv/3'>mevalonate</scene> by the enzyme [[HMG-CoA reductase]]. Production of mevalonate is the rate-limiting and irreversible step in cholesterol synthesis and is the site of action for statins. | Synthesis within the body starts with the mevalonate pathway where two molecules of <scene name='43/430893/Cv/2'>acetyl-CoA</scene> condense to form <scene name='92/929923/Cv/1'>acetoacetyl-CoA</scene>. This is followed by a second condensation between acetyl CoA and acetoacetyl-CoA to form <scene name='92/929923/Cv/2'>3-hydroxy-3-methylglutaryl CoA (HMG-CoA)</scene>. This molecule is then reduced to <scene name='92/929923/Cv/3'>mevalonate</scene> by the enzyme [[HMG-CoA reductase]]. Production of mevalonate is the rate-limiting and irreversible step in cholesterol synthesis and is the site of action for statins. | ||
'''Mevalonate pathway''' | '''Mevalonate pathway''' | ||
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''Geranyl transferase'' | ''Geranyl transferase'' | ||
Three molecules of isopentenyl pyrophosphate condense to form farnesyl pyrophosphate through the action of geranyl transferase. Other names in common use include: | Three molecules of <scene name='92/929923/Cv/8'>isopentenyl pyrophosphate</scene> condense to form <scene name='92/929923/Cv/10'>farnesyl pyrophosphate</scene> through the action of geranyl transferase. Other names in common use include: | ||
*farnesyl-diphosphate synthase | *farnesyl-diphosphate synthase | ||
*geranyl transferase I | *geranyl transferase I | ||
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''Squalene synthase'' | ''Squalene synthase'' | ||
Two molecules of farnesyl pyrophosphate then condense to form squalene by the action of squalene synthase in the endoplasmic reticulum. | Two molecules of <scene name='92/929923/Cv/10'>farnesyl pyrophosphate</scene> then condense to form <scene name='92/929923/Cv/11'>squalene</scene> by the action of squalene synthase in the endoplasmic reticulum. | ||
*[[Squalene synthase]] | *[[Squalene synthase]] | ||