Biochemistry: Enzymes & Enzyme Kinetics

Front 1

Name given to a tightly bound organic molecule necessary for enzyme/protein function.

Back 1

Prosthetic Group

Front 2

Non-protein orgainc molecules or minerals that required for certain enzymes to function:

Back 2

Cofactors

Front 3

_________ are often derived from vitamins.

Back 3

Coenzymes

Front 4

Name given to an enzyme with its cofacor.

Back 4

Holoenzyme

Front 5

Name given to an enzyme without its cofactor.

Back 5

Apoenzyme

Front 6

Coenzyme A is derived from which vitamin and mediatates what type of reaciton?

Back 6

Derived from Pantothenate and mediates acyl transfer.

Front 7

Flavin Coenzymes are derived from which vitamin and mediatates what type of reaciton?

Back 7

Riboflavin (B2) and mediates redox rxns.

Front 8

Nicotinamide Coenzymes are derived from which vitamin and mediatates what type of reaciton?

Back 8

Derived from Niacin and mediate redox rxns.

Front 9

Thiamin phosphate is derived from which vitamin and mediatates what type of reaciton?

Back 9

Thiamine (B1) and mediates decarboxylation.

Front 10

Pernicious Anemia is caused by deficiency of which vitamin?

Back 10

Cobalamin

Front 11

Megaloblastic anemia is caused by deficiency of which vitamin?

Back 11

Folic Acid

Front 12

Pellagra is caused by deficiency of which vitamin?

Back 12

Nicotinamide

Front 13

Beri Beri or WKS is caused by deficiency of which vitamin?

Back 13

Thiamin

Front 14

How does an enzyme affect the overall free energy of a reaction?

Back 14

It doesn't affect it.

Front 15

Cleaves after lysine and arginine:

Back 15

Trypsin

Front 16

Cleaves after Phenyalanine, Tyrosine, and Tryptophan:

Back 16

Chymotrypsin

Front 17

Which three amino acids are found in the catalytic triad in serine proteases?

Back 17

Histidine, Serine, and Aspartate

Front 18

________ must be in the conjugate base state to abstract a proton from serine in the first step of a serine protease reaction.

Back 18

Histidine

Front 19

The initial velocity or rate of a reaction is proportional to _________.

Back 19

Enzyme Concentration- also the amount of enzyme in a sample can be determined from rxn velocity if K is known.

Front 20

Defined as the amount of product formed with time:

Back 20

Velocity of a reaction.
v = dP/dT = K2 [ES]

Front 21

This value is experimentally defined as the substrate concentration where the initial velocity is half the Vmax.

Back 21

Km

Front 22

Rule of thumb: if a metabolic disorder involves a co-factor dependent enzyme _______

Back 22

Check to see if the patient will respond to vitamin supplementation.

Front 23

If K2 is much smaller than K1, Km is a measure of...

Back 23

The affinity of an enzyme for its substrate.

Front 24

An inhibitor directed against HIV protease essential for the virus life cycle. How does it function?

Back 24

Indinavir- functions as a competitive inhibitor.

Front 25

Non-nucleoside inhibitor of the HIV reverse transcriptase- how does it act?

Back 25

Nevirapine- noncompetitive inhibitor, causes closure of the active site

Front 26

Name three ways to regulate enzymes

Back 26

1. Small molecule effectors
2. Covalent modifications
3. Changes in enzyme expression

Front 27

Some enzymes have more than one active site exhibit regulation and binding of a substrate at one site affects other sites

Back 27

Homotropic Effectors

Front 28

Enzymes exhibiting allosteric behavior have ________ velocity vs substrate curves.

Back 28

Sigmoidal

Front 29

Type of allosteric regulation where the effector is different from the substrate and influence the affinity of the enzyme for the substrate.

Back 29

Heterotropic Effectors

Front 30

What is the most common type of modification used to regulate enzyme activity?

Back 30

Phosphorylation

Front 31

Phosphorylation can occur through hydroxyl groups on the side chains of which three amino acids?

Back 31

Ser, Thr, and Tyr

Front 32

_______ modification in an important component of signaling mechanisms that go awry in cancer.

Back 32

Covalent

Front 33

A mutation in the MEK gene can lead to an amino acid substitution that mimics what? What does this activate?

Back 33

Mimics phosphorylation and can activate MEK kinase in the absence of normal growth factor signals causing carcinogenesis.

Front 34

An increase in the enzyme AST levels can be associated with what?

Back 34

Destruction of liver, muscle, and red blood cells.

Front 35

Alanine Aminotransferase (ALT) is highly expressed where? How can it be used?

Back 35

Its expressed in the liver and can help define the liver as the source of increased plasma AST.