Enzymes

Question 1

Coenzyme vs Cofactors

Answer 1

Coenzyme = organic compounds which assist with enzyme function. Cooperate in catalytic action by transiently carrying specific atoms and functional groups i.e. NADP+

Cofactors = inorganic, metal ions that form an important part of the catalytic reaction

Question 2

Manners in which enzyme can be manipulated

Answer 2

1. Inhibited so less of a product is formed or so that substrate remains active for longer i.e. Aceythcholinesterase inhibitors used in the treatment of alzheimers disease or ACE inhibitors which prevent the formation of AT
2. a false substrate is introduced so that a different product is formed often of lower potency i.e. Alphamethyl dopamaine for treatment of high blood pressure (less NA)
3. an inactive substrate can be introduced which will the convert to an active product i.e. L-DOPA in the treatment of parkinsons disease

Question 3

Reaction rate and kinetics

Answer 3

• can increase rate by 5-17 orders of magnitude

Vo= fastest rate, occurs before product inhibition occurs

Km = substrate concentration which allows for one half the initial velocity, aproximates the affinity for the substrate

Question 4

Enzyme Specificity

Answer 4

Enzyme function is fascilitated by the three-dimensional structure of the active site to which substrate molecules bind. Multiple non-covealent bonds occur between the substrate and the enzyme, structure of the active sight will slight change to allow AA resiudes at the active site to contribute to the reaction.

Induced fit model: After initial binding enzyme and substrate will both change in conformation to provide a tighter fit/stronger interaction.

Question 5

Regulation of enzyme function

Answer 5

1. Temp and pH
   - Protein structure will be affected by these conditions
2. Concentration
   - rates of enzyme synthesis can be altered by changes in the transcriptional activity of the gene coding for the enzyme and thus its activity over the long term
   - enzyme amount is also influenced by the rate of degredation of mRNA and degredation of the protein itself
3. Substrate and product concentration.
   - enzymes do not affect Keq, product accumulation will thereby inhibit the reaction progression, removal of product can prevent this.
4. Tissue and cellular location
   - location of enzymes restricts their access ot substrates and hence their function

Question 6

Covalent and non-covalent modulation

Answer 6

Covealent- small molecule binds to the enzyme (i.e phosphoylation)

Non-covealent- Cofactors and coenzymes (provide spatial/temporal control)