The Department of Biochemistry of Medical Faculty Presents now Edited by Attila Sandor SYNTHESIS of CHOLESTEROL and KETONE BODIES

Classification of lipids on chemical basis Fatty acid derivativesIsoprenoids Simple lipidsComplex lipids Triglycerids Vaxes Phospholipids Glycolipids Steroids Carotinoids Author`s picture

A C5 hydrocarbon occurring in oil but not in living organisms Lehn. 4 th ed., p.816

The way of isoprenoid synthesis (1) an enzyme of  -oxidation C2+C2 = C4

The way of isoprenoid synthesis (2) C4+C2 = C6

The way of isoprenoid synthesis (3) to ketone bodies C6

C6-C=C5 C6 The way of isoprenoid synthesis (4) Formation of the final C5 unit

The action of C15 prenyltransferase (3 X 5) C5 C15 C10

The action of C15 squalene synthase (2 X 15)

Strayer 5 th ed , p724 Formation of Squalene (2 X 15 = 30), still straight skeleton Head to Head

Cholesterol -3C Cholesterol C27 -3C

(6C X 5C)-3C = 27C, ring 17C + 2C methyl + 8C side chain Structure, nubering and origins of atoms of cholesterol Strayer, 5 th ed p.733

Chlesterol may be esterified with fatty acids Lehn., 4 th ed. Fig , p.820

polyprenyltransferase C15 prenyltransferase C20 prenyltransferase Compounds built from C5 isoprenoid blocks Lehn., 4th ed. Fig , p.828

The way of isoprenoid synthesis (3) to ketone bodies C6

HMG-CoA is a branchpoint Cleavage enzyme Reductase HMG-CoA synthase Ketone bodies Cholesterol Strayer, 5 th ed p.723

The two ketone bodies are interchangable

The activation of acetoacetate for the metabolism

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