Workshop: Applications to biochemistry

Name: _________________________________ Name: ______________________________

Name: _______________________________________

1. Lipoic acid is a redox cofactor that is an essential as it is part of the catalytic pathway for acyl transfer via thioester formation reaction in aerobic metabolism. Balance the redox reaction.

2. NAD (redox forms NAD+ or NADH) nicotinamide adenine dinucleotide is another Redox cofactor (used e.g in glycolysis and other catabolic pathways). The [NAD+] > [NADH] in cells. It is synthesized from niacin or niacinamide (nicotinamide), essential vitamin B3. Balance the redox reaction.

3. When heat is added to proteins, the hydrogen bonding in the secondary structure breaks apart. What are the algebraic signs of H and S for the denaturation process?

4. Heme serves a variety of functions in biochemistry; from oxygen transport to electron transport. The redox potential varies with the R groups and axial ligands. In hemoglobin, CO- binds over 200 times greater to the Fe center than does O2. Based on what you know, explain why.

Answers:

1. 2e- , 2H+

2. 2e-, H+

3. both are positive

4. Carbon monoxide is a stronger ligand for Fe than oxygen because there is better overlap between the metal d orbitals and the LUMO orbitals of CO (inorganic chemists call this back bonding), one can also write resonance structures that illustrate the bonding.

Fe C O Fe C O-

++-Fe C O