[LEC] UNIT 2 Enzymology

Question 1

T or F: Enzymes are specific proteins that catalyze
biochemical reaction without altering the
equilibrium point of the reaction or being consumed
or changed in composition.

Answer 1

T

Question 2

Enzymes are usually present in _______ concentrations

Answer 2

minute

Question 3

Primary structure- This refers to the _____, ______, and _______ of
amino acids in the polypeptide chain. In order to
function properly, proteins must have the correct
sequence of amino acids.

Answer 3

number, type, sequence

Question 4

Secondary structure refers to the commonly formed arrangements
stabilized by______ bonds between nearby amino
acids within the protein molecule.

Answer 4

hydrogen

Question 5

refers to the overall shape of the protein
molecule.

Answer 5

Tertiary structure

Question 6

Quaternary structure results from the
interaction of more than one protein molecule, or
protein subunits, referred to as_______, that
functions as a single unit.

Answer 6

multimer

Question 8

T or F: Clinically significant enzymes are extracellular
proteins that, when cell damage occurs, leak into the
bloodstream, serving as biomarkers for tissue injury
or disease.

Answer 8

F

Intracellular

Question 9

This is the substance acted upon by the enzyme

Answer 9

Substrate

Question 10

A water free cavity, where the substrate interacts
with particular charged amino acid residues

Answer 10

Active site

Question 11

A cavity other than the active site; binds the
regulator molecules

Answer 11

Allosteric site

Question 12

Where do regulator molecules bind?

Answer 12

Allosteric site

Question 13

T or F: Substrate + Enzyme = Enzyme-Substrate Complex reaction is reversible

Answer 13

T

Question 14

These are enzymes with same function but exist in
different forms

Answer 14

Isoenzyme

Question 15

These are forms of enzymes that were
post-transcriptionally modified.

Answer 15

Isoforms

Question 16

These are non-CHON (non-protein) molecules
necessary for enzyme activity such as activators and
coenzymes.

Answer 16

Cofactors

Question 17

Examples of coenzyme

Answer 17

NAD, Niacin, Vitamins

Question 18

Examples of activators

Answer 18

M: Mg, Mn, Ca, Zn
NM: Br, Cl

Question 19

The different forms of isoenzymes may differ in select physical properties, such as:

Answer 19

• Amino acid composition
• Electrophoretic ability
• solubility and resistance to inactivation

Question 20

Isoenzyme elevated in AMI (acute myocardial
infarction)

Answer 20

CK-MB

Question 21

Most abundant CK isoenzyme

Answer 21

CK-MM

Question 22

Most anodic CK isoenzyme

Answer 22

CK-BB

Question 23

This is a coenzyme bound tightly to the enzyme.

Answer 23

Prosthetic group

Question 24

The enzyme portion that is activated by the
prosthetic group.

Answer 24

Apoenzyme

Question 25

Prosthetic group + Apoenzyme

Answer 25

Holoenzyme

Question 26

Inactive precursor of an enzyme

Answer 26

Zymogen / Proenzyme

Question 27

adopted a classification system in 1961, with the standards revised in 1972 and 1978.

Answer 27

Enzyme Commission of the International Union of Biochemistry

Question 28

catalyze an oxidation–reduction reaction between two substrates

Answer 28

Oxidoreductase

Question 29

Examples of Oxidoreductase

Answer 29

GLD LD G6PD

Question 30

catalyze the transfer of a group other than hydrogen from one substrate to another

Answer 30

Transferases

Question 31

Examples of Transferases

Answer 31

AST ALT

Question 32

catalyze hydrolysis of various chemical bonds

Answer 32

Hydrolases

Question 33

Catalyze removal of groups from substrates without ALD-Aldolase hydrolysis; the product contains double bonds

Answer 33

Lyases

Question 33

Examples of Hydrolases

Answer 33

ALP ACP

Question 34

Example of Lyase

Answer 34

Aldolase

Question 35

Catalyze the interconversion of geometric, optical, or positional isomers

Answer 35

Isomerases

Question 36

Example of Isomerase

Answer 36

Triosephosphate isomerase

Question 37

Catalyze the joining of two substrate molecules. Coupled with breaking of the pyrophosphate bond in ATP

Answer 37

Ligases

Question 38

Example of Ligase

Answer 38

GSH-S

Question 39

Enzymes play a crucial role in regulating the availability of______ hormones to target tissues

Answer 39

thyroid

Question 40

T or F: Some chemical reactions will occur at a slow rate if there is not enough kinetic energy to drive the reaction to the formation of products (uncatalyzed reaction).

Answer 40

T

Question 41

T or F: There is already a product in the Transition State

Answer 41

F

Question 42

Enzymes ______ the activation energy so that the reaction will be faster

Answer 42

lower

Question 43

Proponent of Lock and Key

Answer 43

Emil Fischer

Question 44

Porponent of Induced-fit

Answer 44

Daniel Koshland

Question 45

refers to the ability of an enzyme to selectively bind to a particular substrate, facilitating a specific biochemical reaction

Answer 45

Enzyme specificity

Question 46

Types of E. specificity

Answer 46

Absolute Group Bond Stereoisomeric

Question 47

Factors affecting E Activity

Answer 47

SEPTIC Substrate conc Enzyme conc pH Temperature Inhibitors Cofactors

Question 48

In a ___ degree increase in temp, there is also a doubling of the reaction

Answer 48

10

Question 49

Level of protein denaturation

Answer 49

40 - 50 C

Question 50

Decreases enzyme activity

Answer 50

Inhibitors

Question 51

At high substrate concentrations, enzyme activity _______ because all active sites are saturated.

Answer 51

plateaus

Question 52

the amount of substrate that will give us half the Vmax

Answer 52

Michaelis' Constant (KM)

Question 53

Hypercolic graph

Answer 53

Michaelis-Menten

Question 54

Slope or Linear graph

Answer 54

Lineweaver-Burk

Question 55

the maximum speed of reaction

Answer 55

Vmax

Question 56

What is the effect of extremely high temperature to enzyme activity?

Answer 56

Denaturation

Question 57

A compound that shares some structural feature found in the substrate will typically physically bind to the same form of the enzyme that the substrate binds, often in the active site of an enzyme, and compete with the substrate for a place in the active site.

Answer 57

Competitive Inhibitor

Question 58

Enzymes may also be sensitive to the presence of other compounds that are called noncompetitive inhibitors.

Answer 58

Non-competitive Inhibitor

Question 59

may be observed in which the inhibitor binds only to the ES complex; increasing substrate concentration results in more ES complexes to which the inhibitor binds and, thereby, increases the inhibition

Answer 59

Uncompetitive Inhibitor

Question 60

Measurement of Enzyme Activity

Answer 60

Product formation ^^^ Substrate concentration vvv Cofactor concentration vvv Altered concentration ^^^

Question 61

1 IU =

Answer 61

1 umol/ min

Question 62

Single measurement at a specific time

Answer 62

Fixed time

Question 63

a.k.a. Continuous monitoring assay

Answer 63

Kinetic Assay

Question 64

This inhibitor will show same Vmax and increased Km in the Limeweaver-Burk Plot. (increased to the right)

Answer 64

Competitive Inhibitor