Synthesis of Fatty Acids.ppt [Autosaved]

11/11/2018

Synthesis of Fatty Acids and Triacylglycerol

Lippincott's Chapter 16

Fatty Acid Synthesis

? Mainly in the Liver

? Requires

? Carbon Source: Acetyl CoA

? Reducing Power: NADPH

8 CH3COO

? Energy Input: ATP

C15H33COO

1

11/11/2018

Why Energy ?

Fatty Acid

Acetyl CoA Go : -ve

Acetyl CoA

Fatty Acid Go : +ve

Why Energy ?

Fatty Acid

Acetyl CoA Go : -ve

Acetyl CoA + n(ATP)

Fatty Acid + n(ADP) Go : -ve

2

11/11/2018

FA Degradation and Synthesis

Acyl CoA (n)

Oxidation

Acyl CoA (n+2)

reduction

Hydration

dehydration

Oxidation

Thyolysis

Acyl CoA (n-2) + Acetyl CoA

reduction condensation

Acyl CoA(n) + Malonyl CoA AcetylCoA

Carboxylation of Acetyl CoA Produces Malonyl CoA

O

CH3-C-CoA

O

O

-OC -CH2-C-CoA

CO2 ATP

ADP + Pi

Acetyl CoA Carboxylase Biotin-Containing Enzyme

3

11/11/2018

Fatty Acid Synthase Catalyzes the remaining steps

? Multifunctional Enzyme Complex ? Dimer of two Identical Chains ? Each has Seven Catalytic Activities

? One activity is Condensing Enzyme with ?SH ? One Domain is known as Acyl Carrier Protein

? Carries Intermediates during Catalysis ? (Acyl, Acetyl and Malonyl Groups) ? A protein joined to Phosphopantheine group ? Reactive SH group

Phosphopantetheine group is part of ACP

and ?

phosphate

-Mercapto ethylamine

Adenine

Ribose

Pantothenic acid

Protein

4

Fatty Acid Synthesis (Overview)

Acetyl-CE (Acyl-CE) + Malonyl ACP

(n)

(3)

CO2

Ketoacyl ACP (n+2)

Acyl ACP

11/11/2018

CH3CO~S-CE + OOC-CH2-CO~ACP

Acetyl

Malonyl-ACP

(Acyl)

CO2 HS-CE O CH3C-CH2-CO~ACP Ketoacyl- ACP

5

11/11/2018

Reduction of the Ketoacyl Group

O

CH3C-CH2-CO~ACP

Ketoacyl- ACP

NADPH

OH l CH3CH-CH2H2O CH3CH=CH-

NADPH

CH3CH2-CH2-CO~ACP

Synthesis of Palmitate by Fatty Acid Synthase

6

11/11/2018

Synthesis of Palmitate by Fatty Acid Synthase (Cont.)

Synthesis of Palmitate (net reaction)

How many cycles of synthesis (Condensation)? * 7 How many Malonyl CoA? * 7 How many Acetyl CoA? * 1 How Many NADPH? * 14

7

Production of Cytosolic Acetyl CoA for FA Synthesis

Inner mitochondrial membrane is immpermiable to Acetyl CoA

11/11/2018

NADH NAD+

Production of NADPH

o Pentose Phosphate Pathway

o NADP- dependent malate Dehydrogenase

NADPH

The Fate of Oxaloacetate

8

 ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download