CAS CH 203 Lecture Notes - Lecture 5: American Chemical Society, Creative Commons License, Mit Opencourseware
Document Summary
Figure by o"reilly science art for mit opencourseware. Cyclization of oxidosqualene: lanosterol is the precursor to cholesterol and steroids. Cyclization of the (3s)-2,3-oxidosqualene to produce lanosterol is catalyzed by lanosterol cyclase. This single enzyme creates 7 asymmetric centers stereospecifically at 37 c, at ph 7! The awesome power of enzymes: definition of a catalyst: an entity (organic, inorganic, organometallic, protein or rna) that increases the rate of a reaction without itself being changed in the overall reaction. A catalyst has no effect on the solution equilibrium of a reaction, it increases the rate of approach to equilibrium: most catalysts in biology are proteins. The exception is the ribosome (the translation factory)! 1: enzymes accelerate the rates of reactions relative to non-enzyme catalyzed reactions by factors of 106 to 1015 (figure 2a). Figure 2b shows non-enzymatic reaction rate constants of reactions found in the cell.
