Biosynthesis of Sterols - II

The first part of the scheme, from acetate, in the form of acetyl CoA, to mevalonate:

line structures for acetyl CoA to mevalonate

Acetyl CoA is ubiquitous as an acetyl transfer agent:

line structure of CoA

Some blather about "energy rich" bonds often accompanies the "active acetate" designation in many textbooks.

Acetyl CoA is an effective acetyl transfer agent because:

Herr Doktor Professor Claisen knew about the chemistry of the first step more than 100 years ago.

It's just a Claisen condensation.

The second step is an aldol condensation, followed by hydrolysis of the thiol ester. The product, 3-hydroxy-3-methyl glutarate is known as HMG.

The final step in this chart is an especially interesting one, which is carried out by an enzyme called HMG reductase.

HMG CoA synthase (1tet), CoA Bound HMG Reductase (1dq8; tetramer) with Bound CoA
and HMG

This enzyme is the enzyme inhibited by the "statin" pharmaceuticals mentioned on the first page.


This page last modified 1:35 PM on Tuesday April 15th, 2014.
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