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Flashcards in Enzymes Deck (17):
0

Vmax

The point at which the enzymes are completely saturated

1

Active site

Binding site of an enzyme

2

How do enzymes differ

By enantiomers
-if its substrate is chiral
-specicifity is huge

3

High Km

Lower affinity for substrate

4

Low Km

Higher sffinity for substrate

5

Half way to Vmax

Km

6

Competitive inhibition

-when an inhibitor competes with the active site of a protein
-does not change Vmax
-imcreases the Km value (less affinity for substrate)

7

Noncompetitive inhibition

-does not bind to the active site
-catalytic reaction doesnt take place
-Vmax goes down but Km remains unchanged

8

Hemoglobin

-has four subunits that can bind oxygen
-has *cooperativity
-when the first subunit binds o2 is makes it easier for the second, then third and fourth
-myoglobin only has a single subunit
-in the tissues theres more co2 and acid which releases the o2 (bohr effect)

9

Bohr effect

-at the tissues were more likely to let the oxygen go
-curve shifts

10

Enzyme regulation

-need a way to turn them on and off
1. Allosteric regulation
2. Phosphorylation
3. Zymogens
4. Cofactors
5. Association with other peptides

11

Allosteric regulation

-you will have other molecules besides the substrate that will bind to the enzyme in some site other than the active site
-sometimes they activate and sometimes they inhibit
-when they binds the protein changes its shape
--if you change its shape you change itd ability to catslyze a rxn

12

A - b - c - enzyme - d - e

Positive and negative feedback

If there is alot of a b or c, you need to activate the enzyme(positive feedback)
-if theres alot of d or e you need to inactivate the enzyme(negative feedback)

13

Phosphorylation

-Also know as covalent modification because youre adding a covalent bond
-adding a phosphate group to an alcohol
-promotes a conformation change in the protein because phosphates have alot of negative charges
-sometimes it activates an enzyme and sometimes it deactivates an enzyme

14

Enzymes that phosphorylate a protein

-kinases(use atp to provide the phosphate)
-phosphorylases (dont use atp)
-phosphatases dephosphorylate a protein

15

Zymogens

-Inactive precursers that become active upon proteolytic cleavage

16

Cofactors

Metal ions or organic molecules