ENZYMES: Nomenclature, Kinetics, and Mechanisms of Catalysis

Question 1

These are biological catalysts which are predominantly protein in nature

Answer 1

Enzymes

Question 2

How do enzymes speed up reactions?

Answer 2

Lowering of activation energy

Question 3

The process of catalysis

Answer 3

Two-step process

Question 4

The first process of catalysis

Answer 4

Enzyme-substrate complex formation

Question 5

Second step in the process of catalysis

Answer 5

Conversion of substrate to product

Question 6

How are enzymes classified?

Answer 6

They are classified in the type of reaction they catalyze.

Question 7

Six classifications of enzyme reactions

Answer 7

Oxidoreductase, Transferase, Hydrolase, Ligase, Lyase, and Isomerase

Question 8

Units involved in measuring enzyme activity

Answer 8

Km, Vmax, and Kcat

Question 9

Factors affecting enzyme activity

Answer 9

Enzyme concentration, substrate concentration, temperature, pH, and the presence of inhibitors.

Question 10

What competes against the substrate in binding to the active site.

Answer 10

Competitive inhibitors

Question 11

What affects enzyme conformation and binding of substrate to the active site?

Answer 11

The binding of non-competitive inhibitors to allosteric region

Question 12

Compounds which an enzyme catalyzes

Answer 12

Substrate

Question 13

Non-protein organic molecule, frequently a B-vitamin, that acts as a co-factor

Answer 13

Coenzyme

Question 14

Non-protein portion of an enzyme that is necessary for catalytic function.

Answer 14

Cofactor

Question 15

The protein part of an enzyme

Answer 15

Apoenzyme

Question 16

The coenzyme or cofactor that is tightly bound to the apoenzyme.

Answer 16

Prosthetic Group

Question 17

The term called for the binding of am apoenzyme and prosthetic enzyme

Answer 17

Holoenzyme

Question 18

A specific portion of the enzyme to which a substrate binds during reaction.

Answer 18

Active site

Question 19

Any process that initiates or increases the activity of an enzyme

Answer 19

Activation

Question 20

The portion on the enzyme surface where inhibitors or activators bind to regulate catalytic reactions.

Answer 20

Allosteric Site

Question 21

Compounds that slow down the rate of reaction

Answer 21

Inhibitors

Question 22

A process that makes an active enzyme less active or inactive.

Answer 22

Inhibition

Question 23

Composition of ribozymes

Answer 23

Nucleic acid

Question 24

The binding of enzyme and subtrate

Answer 24

Enzyme-subtrate complex

Question 25

TRUE OR FALSE. Enzymes are highly selective catalysts

Answer 25

TRUE

Question 26

Enumerate the specificity of enzymes

Answer 26

Bond specificity, group specificity, substrate specificity, optical specificity, geometrical specifity, co-factor specificity.

Question 27

The mechanisms of catalysis

Answer 27

Lock and Key and Induced fit

Question 28

A classification of enzymes that involves the process of oxidation-reduction reactions.

Answer 28

Oxidoreductase

Question 29

An enzyme classification that involves a group transfer process

Answer 29

Transferase

Question 30

An enzyme classification that involves the breaking of bonds in the presence of water.

Answer 30

Hydrolase

Question 31

An enzyme classification that involves the addition or removal of double and triple bonds.

Answer 31

Lyase

Question 32

An enzyme classification that involves isomerization reactions

Answer 32

Isomerase

Question 33

An enzyme classification that involves the formation of new bonds

Answer 33

Ligase

Question 34

The measure of how fast an enzyme-catalyzed reaction happens.

Answer 34

Enzyme activity

Question 35

Considerations in enzyme activity

Answer 35

How fast substrates are utilized and how fast products are formed

Question 36

What happens when there is a proportional increase in enzyme concentration and rate of reaction.

Answer 36

More enzymes mean more molecules to convert substrate to products.

Question 37

The rate of reaction wherein it is directly proportional to substrate concentration.

Answer 37

First order kinetics

Question 38

At high substrate concentration, there is an increase reaction rate plateau because of saturation

Answer 38

Zero order kinetics

Question 39

The basis of catalytic parameters

Answer 39

The effect of substrate concentration to enzyme activity

Question 40

The relationship of Michaelis constant and affinity

Answer 40

Inversely proportional

Question 41

The number of moles of substrate converted to products per mole of enzyme per unit time.

Answer 41

Turnover Number (Kcat)

Question 42

The relationship of temperature and reaction rate

Answer 42

Directly proportional

Question 43

Loss of catalytic activity of enzyme

Answer 43

Denaturation

Question 44

Loss of catalytic activity of enzyme

Answer 44

Denaturation

Question 45

The effect of change in pH on reaction rates

Answer 45

The change in pH alters the charge of amino acid residues found in active site.

Question 46

At which an enzyme exhibits maximum activity (Vmax)

Answer 46

Optimal pH

Question 47

What happens to enzyme activity when pH is not regulated?

Answer 47

Irreversible denaturation occurs causing loss of catalytic activity

Question 48

Types of inhibitors

Answer 48

Competitive, Non-competitive, and Uncompetitive

Question 49

It isva reversible inhibitor that competes against substrate in binding to the active site.

Answer 49

Competitive Inhibitor

Question 50

An inhibitor that binds to allosteric sites and alters enzyme conformation.

Answer 50

Non-competitive Inhibitors