The Organic Chemistry of Metabolic Pathways

The Big Picture

•      Metabolism

–   The collection of reactions that take place in living organisms

•      Catabolism

–   Breakdown of larger molecules to smaller ones

•      Anabolism

–   Making larger molecules from smaller ones

 

Catabolism

•      Hydrolysis

–   Ester (fats and olis) to fatty acids

–   Glycosides to sugars

–   Peptides to amino acids

•      Products of hydrolysis are further broken down to acetyl groups that are attached to acetyl coenzyme A

Acetyl Coenzyme A

 

 

 

Citric Acid Cycle

•      Acetyl groups are oxidized to CO2 in mitochondria releasing energy to the electron transport chain

 

Electron Transport Chain

•      This process makes the nucleotide adenosine triphosphate, ATP

•      ATP is the energy source within cell

 

 

 

 

 

 

 

 

Phosphorylation

 

 

 

 

 

 

 

 

 

 

 

 

 

+ H2O  DG° = +13.8 kJ

Energetically unfavorable and non-spontaneous!

 

 

 

 

 

 

 

ATP Coupling-and Energy Source

Glucose + HPO4-2 à Glucose 6-phosphate + H2O        DG° = +13.8 kJ/mole

          ATP + H2O à ADP + HPO4-2 + H+                               DG° = -30.5 kJ/mole

Glucose + ATP à Glucose 6-phosphate + ADP + H+    DG° = -16.7 kJ/mole

 

Makes it spontaneous!

 

Fat Catabolism

•The Players

–ATP ó  ADT          Phosphorylation

•Energy coupling producing spontaneous reactions

–CoA

–NAD+ ó NADH    Oxidation

•Alcohols to aldehydes and ketones

–FAD ó FADH2      Oxidation

•Introduction of double bonds

 

NAD+ ó NADH/H+

 

 

FAD ó FADH2

 

 

 

Glycerol ð Carbohydrate

 

 

Fatty Acid Length Reduction

 

 

Catabolism of Carbohydrates

•      Glycolysis

•      http://instruct1.cit.cornell.edu/Courses/biomi290/MOVIES/GLYCOLYSIS.HTML

•      http://biotech.icmb.utexas.edu/glycolysis/pathway.html

•      http://www.people.virginia.edu/~rjh9u/glycol.html

•      http://www.jonmaber.demon.co.uk/glysteps/step01b.htm

 

Electron Transport in Mitochondria

•      http://www.people.virginia.edu/~rjh9u/eltrans.html

•      http://www.geocities.com/CapeCanaveral/Lab/5934/

 

The Big Picture

•      http://www.people.virginia.edu/~rjh9u/atpyield.html

 

 

Pyruvate à Acetyl CoA

 

 

Krebs Cycle

•      http://www.ite.sc.edu/dickey/EDTE731/Fall98/Gates/krebs.html

•      http://chemistry.gsu.edu/glactone/PDB/Proteins/Krebs/Krebs.html

•      http://www.jonmaber.demon.co.uk/tcasteps/step01b.htm

 

Anabolism of Fatty Acids

 

 

 

Anabolism Of Carbohydrates

•      http://www.med.unibs.it/~marchesi/gluconeo.html#f16bp

•      http://chemistry.gsu.edu/glactone/PDB/Proteins/glycolys/glyco.html

 

Glucoenogensis