1.4 Enzyme Classification and Kinetics

Question 1

Specialized protein catalysts that accelerate chemical reactions in the biologic system

Answer 1

Enzymes

Question 2

Rate of increased speed in catalyzed reactions

Answer 2

10 to 12 times faster than non-catalyzed reactions

Question 3

The protein part of the enzyme that is inactive until bound to a non-protein cofactor

Answer 3

Apoenzyme

Question 4

The non-protein part of the enzyme that is inactive until bound to an apoenzyme

Answer 4

Cofactor

Question 5

The catalytically active enzyme

Answer 5

Holoenzyme

Question 6

Enzymes requiring metal ions as cofactor

Answer 6

Metallonenzyme

Question 7

Catalyzes the rate imiting or committed step of a metabolic pathway

Answer 7

Regulatory enzyme

Question 8

Different forms of an enzyme which catalyze the same chemical reactions; different degrees of efficiency

Answer 8

Isoenzyme

Question 9

Give the vitamin precursor, transferred chemical group, and enzyme attachment of Thiamine Pyrpophosphate (TPP)

Answer 9

Thiamine (Vit B1)AldehydesPyruvate dehydrogenaseIsocitrate dehydrogenasea-ketogluterate dehydrogenaseTransketolasea-ketoacid dehydrogenase

Question 10

Give the vitamin precursor, transferred chemical group, and enzyme attachment of Flavine Adenine Dinucleotide (FAD)

Answer 10

Riboflavin (Vit B2)ElectronsSuccinate dehydrogenasea-ketoglutarate dehydrogenasePyruvate dehydrogenaseNitric oxide synthase

Question 11

Give the vitamin precursor, transferred chemical group, and enzyme attachment of Nicotinamide Adenine Dinuceotide

Answer 11

Nicotinic Acid (Niacin, Vit B3)Hydride IonLactate dehydrogenaseOther dehydrogenases

Question 12

Give the vitamin precursor, transferred chemical group, and enzyme attachment of Pyridoxal Phosphate

Answer 12

Pyridoxine (Vit B6)Amino groupsGlycogen phosphorylaseALA synthaseHistidine decarboxylaseAlanine aminotransferase

Question 13

Give the vitamin precursor, transferred chemical group, and enzyme attachment of Lipoate

Answer 13

Not required in dietElectrons and acyl groupsPyruvate dehydrogenasea-ketoglutarate dehydrogenase

Question 14

Give the vitamin precursor, transferred chemical group, and enzyme attachment of Coenzyme A

Answer 14

Pathothenic acid and other compoundsAcyl GroupsAcetyl CoA carboxylase

Question 15

Give the vitamin precursor, transferred chemical group, and enzyme attachment of Biocytin

Answer 15

BiotinCo2Pyruvate carboxylaseAcetyl CoA carboxylaseProprionyl CoA carboxylase

Question 16

Give the vitamin precursor, transferred chemical group, and enzyme attachment of 5’-deoxycobalamin

Answer 16

Vit B12H atoms and alkyl groupsMethylmalonyl mutase

Question 17

Give the vitamin precursor, transferred chemical group, and enzyme attachment of Tetrahydroflorate

Answer 17

Folic acid1 C groupsThymidilate synthase

Question 18

Target enzyme and disease of Amrubicin

Answer 18

Topoisomerase IICancer

Question 19

Target enzyme and disease of Antabuse

Answer 19

Aldehyde dehydrogenaseAlcoholism

Question 20

Target enzyme and disease of Captopril

Answer 20

ACEHypertension

Question 21

Target enzyme and disease of Celebrex

Answer 21

Cyclooxygenase-2Arthritis

Question 22

Target enzyme and disease of Digitoxin

Answer 22

Na-K-Atpase pumpHeart problems

Question 23

Target enzyme and disease of Agenerase

Answer 23

HIV ProteaseAIDS

Question 24

Target enzyme and disease of Lipitor

Answer 24

HMG CoA reductaseHypercholesterolemia

Question 25

Target enzyme and disease of Viagra

Answer 25

PhosphodiesteraseErectile dysfunction

Question 26

Enzyme activity regulation where the product inhibits its own synthesis

Answer 26

Feedback Inhibition

Question 27

Enzyme activity regulation where the binding of an allosteric modulator changes activity of the active site

Answer 27

Allosteric modification

Question 28

Enzyme activity regulation where the enzyme is phosphorylated or dephosphorylated to activate or inactivate the enzyme

Answer 28

Covalent modification

Question 29

Enzyme activity regulation where a protein is first produced in an inactive state and is activated after protein cleavage

Answer 29

Zymogen activation

Question 30

Happens when the temperature is greater than optimum temperature

Answer 30

Decreased velocity and denaturation of enzymeDestruction of secondary and tertiary structures of the enzyme

Question 31

Major enzyme seen in cardiac injury (myocardial infarction). Indicate time of rise, peak, and duration of elevation (days).

Answer 31

TroponinRises 3-6 hours after injuryPeaks 12-16 hoursStays elevated in 5-14 daysCreatinine KinaseBegins 4-6 hours after MIPeak 24 hoursreturn to normal in 3-5 daysLactate dehydrogenase (diagnostic for patients admitted more than 48 hours after infarction)Peak at 36-40 hours after MILevels return to normal in 5-14 daysAspartate aminotransferase (not diagnostic since also found in liver)Rise within 8 hours after MIPeak 24-36 hoursReturns to normal within 3-7 days

Question 32

Two models of enzyme substrate binding

Answer 32

Lock and KeyInduced fit model

Question 33

Saturation curves

Answer 33

Michaelis-Menten EquationLineweaver-Burke double reciprocal

Question 34

inverse measure of enzyme affinity for substrate

Answer 34

Km

Question 35

Control mehcanisms for enzuumes

Answer 35

Feedback inhibitionAllosteric modificationCovalent modificationZymogen activationInduction/repression of enzyme synthesis

Question 36

Factors affecting enzyme activity

Answer 36

TemperaturepHSubstrate concentrationCo-factors