MSc "Microbiology and Biochemistry"

Questions „Enzymes: Mechanisms and Regulation“ (Tittmann, lecture 1)

1.) Please discuss common and different features of chemical vs. enzymatic catalysts!
2.) What are the underlying principles and mechanisms of enzymic catalysis?
3.) Which organic reactions require acid/base catalysis? Specify examples. Please discuss
kinetic methods to estimate dissociation constants (pKa values) of acid/base catalysts.
4.) Covalent catalysis and proteases: What are the individual chemical roles of the amino
acids constituting the catalytic triad? How is substrate specificity of the different proteases
5.) Metal ion catalysis: why is it required at all? Discuss different reaction types and chemical
activation conferred by metal ions.
6.) Lysozyme: What are the mechanistic differences and commonalities of the classic ‘Phillips
mechanism’ and the alternative ‘covalent mechanism’? Please include aspects of sugar
conformers and their stability/destabilisation, steric stress etc.

Questions „Enzymes: Mechanisms and Regulation“ (Tittmann, lecture 2)
1.) Please specify the different types of reversibly binding inhibitors and give examples. In which way are steady-state constants affected by those inhibitors?
2.) Irreversible inhibitors: why can certain inhibitors bind (and/or react) irreversibly with enzymes?
3.) Please specify different principles of enzyme regulation and name examples. Please explain why different modes of allosteric activation / inhibition and covalent modifications exist.
4.) Disclose commonalities and differences for regulation by phosphorylation and by proteolytic cleavage.