Biochem L5R

Question 1

What is the Michaelis-Menten, what are the values associated with the equation?

Answer 1

1.VELOCITY expressed as the rate of substrate to product conversion per min. & velocity depends on concentration of [s].

2. Michaelis-Menten equaiton explains change in velocity related to substrate concentration.

km=affinity of enzme to a particular substrate.

small Km= High affinity

large Km= low affinity

Vmax= Maximal reaction velociyt

Question 2

Differentiate between Lineweaver and Burk Equation.

Answer 2

1. Lineweaver-Burk equation ( double reciprocal plot.)
   - Required less points to make a plot
   - Make the extapolation easier.
2. Liner slope

Question 3

what do Glucokinase and hexokinase do? explain the chart.

Answer 3

1.Isozymes catalyze 1st step in glucose metabolism.

Ex. Hexokinase I allows RBCs to use glucose when plasma level is low.

Ex. Glucokinase found in liver & pancreatic beta cells

Promotes storage of glucose or insulin secretion.

Need help explaining the chart and what it means:

Glucose phoshorylation in liver…

1.increases and glucose level increase

2.Down as blood glucose levels fall

3.High Km of glucokinase prometes glucose storage

Question 4

What are the major differences between Noncompetitive and Competitive inhibition? what is the following graph.

Answer 4

1. Inhibitor, substance that can decrease the velocity of reaction.
   - Reversible inhibitor: binds to enzyme through noncovalent bonds, enzyme can funtion porperly by dilution or uping [s]
   - Irreversible Inhibition: Enzyme does not regain activity upon dilution. usually by covalent interacton of Inhibitor and Enzyme
2. two kinds

1.Competitive : Inh. binds to same site of substrate,

• Reversible by uping [s]
• Vmax doesnt change
• Km increased, more [s] needed to acheive 1/2 Vmax
  2. Noncompetitive: Inh. and substrate bind at different sites on the enzyme.
• Inhibitor can bind to free enzyme or ES complex.
• Irrevirsible
• lower Vmax
• Km stays the same ( no interference with substrate binding to enzyme.)

Question 5

what are the different types of processes, to regulate enzymes activity by conformational changes?

Answer 5

1. We can regulate enzymes activity by conformational changes.
2. Allosteric activation or inhbition:
3. Phosphorylation or other posttranslational modifications
4. Protein-protein interaction
5. proteolytic cleavage