1. Metabolism Basics
Title - metabolism basics

2. Two faces of metabolism
Catabolism - degradation
Anabolism - biosynthesis
There are two faces to metabolism - breakdown (degradation) and synthesis

3. Catabolism Catabolic sequences yield energy Oxidative ATP, NADH
Catabolic sequences yield energy. The oxidation of NADH to NAD+ is catalyzed by the electron transport chain and the synthesis of ATP is catalyzed in the process of oxidative phosphorylation (oxphos).

4. Catabolic Pathways ATP, NADH Glycolysis GTP, NADH, FADH2
NADPH
ATP
ATP, NADPH
Glycolysis
TCA (Krebs) cycle
-oxidation of fatty acids
Oxidation of -keto acids (from amino acids)
Hexose monophosphate path
Oxidative phosphorylation
Photophosphorylation
Examples of catabolic pathways with the compounds produced.

5. Catabolism is Convergent
The Krebs citric acid cycles collects and completely oxidizes the acetyls from carbohydrate, fat and protein catabolism. The electron transport chain and oxphos regenerate the coenzymes and make ATP. The oxygen is utilized in the process - not produced as intimated in the figure.

6. Catabolic Regulation Allosteric Covalent Hormonal
Altered gene expression
ATP and PFK-1
Phosphorylation of glycogen phosphorylase
Epinephrine 
[cAMP]
Protein phosphorylation
AA oxidizing enzymes
Metabolic process are regulated by various means - examples are listed.

7. Localization of Catabolism
Mitochondria (matrix, membrane)
-oxidation
AA oxidation
Pyruvate oxidation
Oxidative phosphorylation
Catabolism may occur in specific sites within the cell. The mitochodria does lots of oxidations.

8. Localization of Catabolism
Cytosol
Glycolysis
Hexose-P
Chloroplast
Photophosphorylation
Other compartments are also involved.

9. Compartmentation of Catabolism
With two compartments there must be separate pools and there is exchange between tem catalyzed by carriers.

10. Tissue Specialization in Catabolism
Glycolysis
Krebs Cycle
Fatty acid oxidation
Urea cycle
-keto acid oxidation
Every Cell
Almost every cell (not RBC)
Most tissues (not brain)
Liver
Liver (except branched chains)
Certain tissues carry out specialized catabolic reactions.

11. Irreversibility of Catabolism
The breakdown is irreversible. Energy in the form of ATP is a product.

12. Summary: Catabolism Oxidative Convergent Tightly regulated
Localized intracellularly
Separate pools
Tissue-specific
Universal
“Irreversible”
Exergonic
The key facts of catabolism.

13. Anabolism (Biosynthesis)
Reductive
Cofactor: usually NADPH
Pentose-P pathway
Glutamate dehydrogenase
Photosynthetic electron transfer
NADH + NADP NAD+ + NADPH
The other side of the coin is biosynthesis (anabolism). Reducing power and energy usually required.

14. Anabolism: Divergent
There are standard simple precursors with divergent pathways leading to specific products.

15. Anabolism: Regulation
Anabolism is also regulated. Glutamine goes to several different products.

16. Anabolism: Localization in Cells
Gluconeogenesis
Fatty acid synthesis
Glycogen synthesis
Starch synthesis
Amino acid synthesis
Cytosol (mainly)
Cytosol
(Chloroplasts)
Chloroplast
Anabolism is also localized.
Distinct pools:
In mitos: [NAD+]/[NADH] high
In cytosol: [NADPH]/[NADP+] high

17. Anabolism: Tissue-Specific
Gluconeogenesis
Fatty acid synthesis
Steroid hormones
Glycogen synthesis
Vitamins
Liver (kidney)
Liver, mammary gland
Adrenal cortex, ovaries, testes
Muscle, liver
No tissue; thus required in diet
Anabolism is also tissue-specific.

18. Anabolism: “Irreversible”
Anabolism is also irreversible. Thus catabolism and anabolism are like a pair of one-way streets.

19. Two Separate Pathways Catabolic path  Anabolic path
Two separate pathways - at least for a few reactions.

20. Reciprocal Regulation
Anabolic and catabolic pathways are reciprocally regulated
Regulation occurs at reactions unique to the path
Same regulator has opposite effect on path
Epinephrine
Stimulates -oxidation
Inhibits fatty acid synthesis
The regulation occurs doubly - activation of one pathway and inhibition of the other and visa versa.

21. Summary: Anabolism Reductive (NADPH) Divergent Regulated Localized
At branch points
Reciprocally with catabolism
Localized
Generally in the cytosol
Anabolism facts

22. Summary: Anabolism Tissue-specific Liver “Irreversible” Use of ATP
Separate path from catabolism
More facts