Enzyme Part 1

Question 1

> Greek word en

Answer 1

means “in”

Question 2

> zyme

Answer 2

which means “yeast”

Question 3

> is an organic compound that act as a catalyst for a biochemical reaction; increases rate of reaction butare not changed in the process
water-soluble, globular proteins
Features:
a) Enhance reaction rates (pH 7.4 and 37°C). An enzyme catalyzed reaction can be 106 to 1012 times faster than uncatalyzed reaction
b) Enzymes are very specific.

Answer 3

Enzyme

Question 4

> Features:

Answer 4

a) Enhance reaction rates (pH 7.4 and 37°C). An enzyme catalyzed reaction can be 106 to 1012 times faster than uncatalyzed reaction
b) Enzymes are very specific.

Question 5

STRUCTURE OF ENZYME

an enzyme composed only of protein.

Answer 5

• simple enzyme

Question 6

an enzyme that has a nonprotein part in addition to the protein part.

Answer 6

conjugated enzyme

Question 7

is the protein part of a conjugated enzyme

Answer 7

> apoenzyme

Question 8

is the nonprotein part of a conjugated
enzyme

Answer 8

cofactor

Question 9

is the biochemically active conjugated enzyme produced from an apoenzyme and a cofactor
Apoenzyme + cofactor = holoenzyme

Answer 9

holoenzyme

Question 10

Why do apoenzymes need cofactors?

Answer 10

• A cofactor is a non-protein chemical compound that is required for the protein’s biological activity.
• Cofactors can be considered “helper molecules” that assist enzymes in their action. Cofactors can be ions or organic molecules (called coenzymes).

Question 11

is a small organic molecule that serves as a cofactor in a conjugated enzyme.

Answer 11

Coenzyme

Question 12

Inorganic ion cofactors include zinc, magnesium, manganese, and iron; chloride occasionally acts as a

Answer 12

Cofactor

Question 13

• It is bound tightly to the enzyme and is not dissociated even after several extensive steps of purification.

Answer 13

Metallo-enzymes

Question 14

are the focal points for nomenclature.

Answer 14

type of reaction catalyzed and substrate

Question 15

is the reactant in an enzyme-catalyzed reaction; it is the substance upon which the enzyme”acts”

Answer 15

substrate

Question 16

Few enzymes exist in their inactive form called.

Answer 16

proenzymes or zymogens

Question 17

• become active after prior modification in its structure by certain agents. Many times the active form of enzyme acts on zymogen and catalyzes its conversion into active form - process called AUTOCATALYSIS

Answer 17

Zymogens

Question 18

PROPERTIES OF ENZYMES

• special pocket or cleft within the enzyme molecule
• contains amino acids side chains that participate in substrate binding and catalysis

Answer 18

Active sites

Question 19

• Highly efficient (103
• 108) times faster than uncatalyzed reactions

Answer 19

Catalytic efficiency

Question 20

• highly specific, interacting only with one or a few substrates and catalyzing only one type of chemical reaction

Answer 20

Specificity

Question 21

• some enzymes require molecules other than proteins for enzymatic activity
• Holoenzymes refers to the active enzymes with its nonprotein component, whereas the enzyme without its nonprotein moiety is termed an apoenzyme and is inactive.
  If the nonprotein is a metal ion (Zn2+ or Fe2+), it is called a cofactor
  If it is a small organic molecule, it is termed as coenzyme.
• Coenzymes that only transiently associate with the enzyme are called cosubstrates.
• Cosubstrates dissociate from the enzyme in an altered state. (ex. NAD+)

Answer 21

Holoenzymes

Question 22

• Enzyme activity can be regulated, that is, increased or decreased, so that the rate of product formation responds to cellular need.

Answer 22

Regulation

Question 23

• Many enzymes are localized in specific organelles within the cell. Such compartmentalization serves to isolate the reaction substrate or product from other competing reactions. This provides a favorable environment for the present in the cel into purpose tipathways of enzymes

Answer 23

Location within the cell

Question 24

requires a coenzyme that is oxidized or reduced as the substrate is reduced or oxidized.
Lactate dehydrogenase is an oxidoreductase that removes hydrogen atoms from a molecule.

Answer 24

Oxidoreductase

Question 25

is an oxidation that increases the number of C-O bonds and/or decreases the number of C-H bonds.

Answer 25

organic oxidation reaction

Question 26

is a reduction that decreases the number of C-O bonds and/or increases the number of C-H bonds.

Answer 26

An organic reduction reaction

Question 27

an enzyme that catalyzes the transfer of a functional group from one molecule to another.

Answer 27

Transferase

Question 28

Two subtypes of transferase:

catalyzes the transfer of an amino group from one molecule to another;

Answer 28

Transaminase

Question 29

Two subtypes of transferase:

-catalyze the transfer of a phosphate group from adenosine triphosphate (ATP) to give adenosine diphosphate
(ADP) and a phosphorylated product (a product containing an additional phosphate group)

Answer 29

Kinases

Question 30

• an enzyme that catalyzes a hydrolysis reaction in which the addition of a water molecule to a bond causes the bond to break. Hydrolysis are central to the process of digestion.

Answer 30

Hydrolase

Question 31

enzymes digest fatty
substrates.

Answer 31

Lipase

Question 32

enzymes digest protein substrates.

Answer 32

Protease

Question 33

enzymes digest carbohydrate substrates.

Answer 33

Carbohydrase

Question 34

is an enzyme that catalyzes the addition of a group to a double bond or the removal of a group to form a double bond in a manner that does not involve hydrolysis or oxidation.

Answer 34

Lyase

Question 35

effects the removal of the components of water from a double bond

Answer 35

Dehydratase

Question 36

effects the addition of the components of water to a double bond

Answer 36

Hydratase

Question 37

an enzyme that catalyzes the isomerization (rearrangement of atoms) of a substrate in a reaction, converting it into a molecule isomeric with itself.
• There is only one reactant and one product in reactions where isomerases are operative.

Answer 37

Isomerase

Question 38

is an enzyme that catalyzes the bonding together of two molecules into one with the participation of ATP.

Answer 38

Ligase