BIOCHEM: ENZYME

Question 1

Catalysts for biochemical reactions

Answer 1

Enzymes

Question 2

the substance on which an enzyme acts

Answer 2

Substrate

Question 3

–substance produced by the action of enzyme on substrate

Answer 3

Product

Question 4

– region or domain where the substrate binds

Answer 4

Active site

Question 5

– nonprotein component that assists in catalysis

Answer 5

• Cofactor

Question 6

composed entirely of protein (AA chains)

Answer 6

Simple enzyme

Question 7

– protein + nonprotein part

Answer 7

Conjugated enzyme

Question 8

– biochemically active conjugated enzyme

Answer 8

Holoenzyme

Question 9

provide additional chemically reactive functional groups
* May be permanently or temporarily bonded to the apoenzyme

Answer 9

Cofactors

Question 10

– small organic molecules ← Vitamins

Answer 10

Coenzymes

Question 11

– Zn2+, Mg2+, Fe2+, Fe3+, Cu+, Cu2+ ← Minerals

Answer 11

Metal ions

Question 12

• small portion that actually participates in the
  interaction with a substrate

Answer 12

Active Site

Question 13

Intermediate reaction species that is formed
when the substrate binds to the active site

Answer 13

Enzyme-Substrate complex

Question 14

The enzyme has enough
flexibility to allow for small
changes in its shape or geometry

Answer 14

Induced Fit Model

Question 15

The active site has a fixed, rigid
geometrical conformation

Answer 15

Lock and Key Model

Question 16

– enzyme catalyzes only one reaction;
e.g. catalase

Answer 16

Absolute specificity

Question 17

enzyme acts only on molecules with a specific
functional group

Answer 17

Group specificity

Question 18

– enzyme acts only on a specific chemical bond
e.g. phosphatase

Answer 18

Linkage specificity

Question 19

– enzyme acts only on a particular
stereoisomer

Answer 19

Stereochemical specificity

Question 20

Catalyzes an oxidation-reduction (redox) reaction

Answer 20

Oxidoreductase

Question 21

Catalyzes transfer of a functional group from one molecule to another

Answer 21

Transferase

Question 22

– catalyzes the transfer of an amino group

Answer 22

Transaminases

Question 23

catalyzes the transfer of a phosphate group

Answer 23

• Kinases

Question 24

Catalyzes a hydrolysis reaction

Answer 24

Hydrolase

Question 25

Catalyzes rearrangement of atoms (isomerization) of a substrate in a reaction, converting it into a molecule isomeric with itself

Answer 25

Isomerase

Question 25

Catalyzes the addition of a group to a double bond OR removal of a group to form a double bond in a manner that DOES NOT involve hydrolysis or oxidation

Answer 25

Lyase

Question 26

Catalyzes the bonding together of two molecules into one with the use of ATP

Answer 26

Ligase

Question 27

Measure of kinetic energy of molecules

Answer 27

Temperature

Question 28

– temperature at which an enzyme exhibits maximum activity

Answer 28

Optimum temperature

Question 29

Can lead to changes on the charge of acidic and basic amino acids located on the active site

Answer 29

pH

Question 30

Enzyme concentration is constant + Substrate concentration is increased → faster reaction rate until it reaches the maximum reaction rate (velocity)

Answer 30

Substrate Concentration

Question 31

the number of substrate molecules transformed per minute by one molecule of enzyme under optimum conditions

Answer 31

Turnover number

Question 32

molecule that sufficiently resembles the substrate in shape and charge distribution that it competes with the substrate for occupancy of the active site

Answer 32

Competitive inhibitor

Question 33

as substrate concentration increases and enzymes become fully occupied

Answer 33

SATURATION

Question 34

molecule that decreases enzyme activity by binding to a site other than the active site

Answer 34

Noncompetitive inhibitor

Question 35

molecule that inactivates enzymes by forming strong covalent bonds to an amino acid side chain at the active site

Answer 35

Irreversible inhibitor

Question 36

Process in which activation or inhibition of the first reaction in a sequence is controlled by a product of the reaction sequence

Answer 36

Feedback Control

Question 37

inactive precursor of proteolytic enzymes

Answer 37

Zymogen (proenzyme)

Question 38

adding or removing a group from enzyme by forming or breaking a covalent bond

Answer 38

Covalent modification

Question 39

addition of a phosphate group ← kinases

Answer 39

Phosphorylation –

Question 40

– removal of a phosphate group ← phosphatases

Answer 40

Dephosphorylation

Question 41

Certain enzymes are not normally found in the blood and produced only in certain types of cells

Answer 41

Diagnosis