Enzymes

Question 1

Enzyme activity

Answer 1

amount of substrate turned inot product

Question 2

specific activity

Answer 2

the activity of an enzyme per milligram of total protein

the amount of substrate converted, per mg protein in the enzyme preparation, per unit of time

Question 3

turnover nummber

Answer 3

substrate molecules converted to product in a given unit

Question 4

catalytic constant

Answer 4

moles product per second/moles active site

The number of molecules of substrate converted to product per unit time, when the enzyme is working at maximum efficiency.

Question 5

km

Answer 5

substrate concentration at a velocity where vmax/2 at particular ezyme concentration

Question 6

competetive inhibition

Answer 6

compete with substrate for active site, vmax is same, km increases

Question 7

non-competetive

Answer 7

inhibitor binds to another site than avtive site and reduces enzyme avtivity.
Km is same, vmax decreases

Question 8

un-competetive

Answer 8

Inhibitor binds only to the complex formed between the enzyme and the substrate.
Km and vmax decreases

Question 9

Effect of enzymes

1. Activation energy:
2. gibbs free energy
3. reaction mechanism
4. equilibrium state
5. time to reach equilibrium

Answer 9

1. Decreases
2. No change
3. changes
4. No change
5. decreases

Question 10

Types of enzymes

Answer 10

Oxidoreductases
ligases
lyases
isomearses
transferases

Question 11

Acid/base catalysis

Answer 11

A.a side chains contribute in catalysis by acting as acid/base

Question 12

Specific acid/base catalysis

Answer 12

Only dependent of H+ and OH, independent of concentration of acids/bases

Question 13

Proteases

Answer 13

Enzyme that cuts proteins by hyrdolzing peptide bonds

Question 14

Serine-protease

Answer 14

Cuts protein by hydrolyzing peptide bonds using serine in the active site of the enzyme

Question 15

Inbibitor of ser protease

Answer 15

di-isopropyl-fluro-phosphate

irreversible inhibitor

Question 16

Zygmoens/proenzyme

Answer 16

Inactive enzyme, can be activated by hydrolysis

Question 17

enzyme induction

Answer 17

Process in which molecule induces expression of enzyme

Question 18

specificity of serine protases

Answer 18

They are charachterized by distinct structure

where they can be substare specified as trypsin like, chymotrypisn, elastase like

Question 19

Irreversible covalent modification

Answer 19

conversion of inavtive proenzyme to active enzyme by hydrolyzing peptide bonds

Question 20

Reversible covalent modification

Answer 20

Phosphorylation/ dephosphosphorylation on the enzyme

Question 21

enzyme repression

Answer 21

Reprseeor molecule that prevent production of enzyme.

Question 22

Protein kinase

Answer 22

enzymes modifying enzymes by adding a phosphate group

Question 23

Hill coeficcient

Answer 23

measuring the cooperativity between subunits

Question 24

Prosthetic group

Answer 24

Small molecule participating in substrate binding and catalysis
Ex. FAD, bind by covalent, non-covalent

Question 25

Cofactor

Answer 25

Small molecule participating in substrate binding and catalysis
Bind in a dissociable manner

Question 26

Coenzymes

Answer 26

Small molecule participating in substrate binding and catalysis
Ex: Nadh, transports substrates from one place to another

Question 27

Sirtuin

Answer 27

NAD-dependent deacetylases of histones

Play role in silencing, supression of genes near telomeres.

Question 28

Catalysis Constant

Answer 28

Catalytic efficiency of enzymes, increasing the rate of reactions which results in a more efficient chemical reaction within a biological systems.

Question 29

Line - weaver burke plo

Answer 29

is a graphical representation of the of enzyme kinetics where the y axis is 1/V and the x axis is 1/s. The y axis intercept is 1/vmax and the x axis is -1/Km. Slope is Km/Vmax. It demonstrates the inhibition type on an enzyme.

Question 30

In active site of chymptrypsin, trypsin, elastase

Answer 30

chymotrypisn: Phe, Tyr, Trp
trypsin: Arg,Lys
elastase: Gly,Ala, Ser

Question 31

specific constant

Answer 31

kcat/ km