Chapter 4 Definitions/Concepts

Question 1

Cofactors

Answer 1

Nonprotein portions of an enzyme required for action

Question 2

Coenzyme

Answer 2

An organic cofactor required for enzyme activity

Question 3

Apoenzyme

Answer 3

An enzyme lacking its cofactor, coenzyme or prosthetic groups

Question 4

Holoenzyme

Answer 4

Apoenzyme and its cofactor, coenzyme or prosthetic groups. Essentially everything needed for catalytic activity

Question 5

Metalloenzyme

Answer 5

Apoenzyme and it’s metal iron cofactor

Question 6

Prosthetic group

Answer 6

Tightly bound coenzyme

Question 7

Stereospecificity

Answer 7

The arrangement of the substrate atoms in three-dimensional space

Question 8

Active Site

Answer 8

Region on the enzyme that is directly responsible for interacting with the reacting molecules

Question 9

Proenzyme or Zymogen

Answer 9

An enzyme in its inactive form

Question 10

Six basic enzyme types

Answer 10

Oxidoreductases
Transferases
Hydrolase's
Lyases
Isomerases
Ligases or Synthertases

Question 11

Oxidoreductases

Answer 11

Redox reactions

Question 12

Transferases

Answer 12

The transfer groups of atoms

Question 13

Hydrolases

Answer 13

Hydrolysis

Question 14

Lyases

Answer 14

Addition to a double bond or information of a double bond

Question 15

Isomerases

Answer 15

The isomerization of molecules

Question 16

Ligases or Synthertases

Answer 16

The joining of two molecules

Question 17

Oxidation

Answer 17

The loss of one or more electrons, gain of oxygen or loss of hydrogen

Question 18

Reduction

Answer 18

Gain of one or more electrons, loss of oxygen or gain of hydrogen

Question 19

Aminotransferase

Answer 19

Transfers an amino group

Question 20

Phosphotransferase

Answer 20

Transfers of phosphoryl group

Question 21

Phosphatase

Answer 21

Catalyzes the hydrolysis of a monophosphate ester

Question 22

Peptidase

Answer 22

Catalyzes the hydrolysis of a peptide bond

Question 23

Deaminase

Answer 23

Aids in the removal of ammonia

Question 24

Decarboxylase

Answer 24

Catalyzes the loss of CO2

Question 25

Pyruvate carboxylase

Answer 25

Catalyzes the formation of a C-C bond

Question 26

Acetyl CoA Synthetase

Answer 26

Catalyzed formation of a C-S bond

Question 27

Enzyme-substrate complex

Answer 27

The substrate in some way binds to the enzymes active site

Question 28

Endergonic

Answer 28

Non spontaneous and energy is absorbed

Question 29

Michaelis constant

Answer 29

The substrate concentration producing a rate of one half the maximum velocity

Question 30

Allosteric

Answer 30

Regulatory

Question 31

Michaelis-Menten equation

Answer 31

V=Vmax[S]/[S]+Km

Question 32

Line weaver-Burk Plot

Answer 32

Double reciprocal plot derived from the Michaelis-Menten equation and only gives a general idea of KM and Vmax

Question 33

Enzyme regulation

Answer 33

Allosteric control, multiple enzyme forms, covalent modification, proteolytic activation.

Question 34

Allosteric control

Answer 34

A regulatory enzyme binds to a regulator site inducing a confirmation will change that turns the enzyme into its active form

Question 35

Multiple enzyme forms

Answer 35

Isozymes or Isoenzymes have slight differences in structure

Question 36

Covalent modification

Answer 36

The attachment of a group alters the enzymes activity, this is a reversible reaction catalyzed by protein kinases

Question 37

Proteolytic Activation

Answer 37

An inactive form of the enzyme goes through irreversible activation.

Question 38

Motif

Answer 38

Recognizable folding pattern involving 2 or more elements of secondary structure

Question 39

Multimer

Answer 39

Multisubunit protein

Question 40

Oligomer

Answer 40

A multiuser with few subunits

Question 41

Protomer

Answer 41

Repeating structural subunit in multimeric proteins

Question 42

Hemoglobin

Answer 42

A tetramer/diamer of AB protomers

Question 43

Denaturation

Answer 43

Loss of 3D structure to the loss of function, doesn't require complete unfolding.

Question 44

Ways of denaturing

Answer 44

Heat, pH, solvents, solutes or detergents

Question 45

Renaturation

Answer 45

The regaining of the native conformation when returned to native conditions in which the conformation is stable.

Question 46

Ribonuclease A

Answer 46

Can be completely denatured with urea where disulfide bonds are broken and the structure becomes random coil. When removed from the urea and reducing agent, it returns to the correct tertiary structure are regains catalytic activity.

Question 47

Levinthal's Paradox

Answer 47

10^77 years for E. Coli to try all possible conformations. For this reason protein folding can't be random, there must be a shortcut.

Question 48

3 Models for Protein Folding

Answer 48

1. Local structures form first then longer range interactions until the final structure is formed. 2. Spontaneous collapse of the polypeptide into the compact state controlled by hydrophobic and polar residues. 3. A combination of 1 and 2.

Question 49

Molecular Chaperones

Answer 49

Proteins that interact with polypeptides to facilitate proper folding. Two main types; Heat shock proteins and Chaperonins

Question 50

Heat Shock Proteins

Answer 50

Protect proteins when there are elevated temperatures in cells. Also help keep certain proteins unfolded until transported across the membrane.

Question 51

Chaperonins

Answer 51

Takes in unfolded proteins into its chamber. Caps the chamber then undergoes a conformational change, forcing the protein to fold.

Question 52

Protein Disulfide Isomerase (PDI)

Answer 52

Enzyme that catalyzes the interchange or shuffling of disulfide bonds.

Question 53

Peptide prolyl cis-trans Isomerase (PPI)

Answer 53

Catalyzes the interconversion of the cis-trans isomers of Proline residue peptide bonds.