Regulation of Enzymes

Question 1

In regards to synthesis and degradation, since Vmax = K3[Etotal], one way to increase or decrease activity is to increase or decrease ____

Answer 1

[Etotal]

Question 2

By keeping enzymes, cofactors and substrates of two conflicting pathways physically separate, futile cycling of substrates is avoided. Give an example of this.

Answer 2

FA synthesis occurs in the cytosol

FA oxidation occurs in the mitochondria

Question 3

Many hormones produce “second messengers” which are allosteric effectors of various enzymes and tissues. One popular second messenger that binds various enzymes, altering their activity is ___

Answer 3

cAMP

Question 4

Some hormones increase the cytosolic ____, which interacts with a protein called calmodulin.

Answer 4

[Ca2+]

Question 5

What happens to the Ca2+ - calmodulin complex?

Answer 5

affects the activity of a number of proteins

Question 6

Phosphorylation is a type of ___ regulation

Answer 6

covalent

Question 7

Phosphorylation is accomplished by a protein ___ which may be very specific for the enzyme or protein to be phosphorylated or may be broad in its specificity

Answer 7

kinase

Question 8

Dephosphorylation is accomplished by a protein ____

Answer 8

phosphatase

Question 9

In regards to proteolytic activation, some enzymes are synthesized in inactive form (zymogen or proenzyme). How are they activated?

Answer 9

proteolytic cleavage

Question 10

What are some examples of digestive proteases (proteolytic enzymes)? Coagulation zymogens?

Answer 10

digestive proteases: trypsinogen, chymotripsinogen

coagulation zymogens: fibrinogen, prothrombin, etc

Question 11

Name the three things that increase glycogen phosphorylase activity

Answer 11

1. allosteric effector AMP
2. phosphorylation of the enzyme
3. binding of Ca2+ - calmodulin