CC LEC 2 - Enzymes

Question 1

most enzymes react at pH __but some are active in wider pH ranges

Answer 1

7.0- 8.0,

Question 2

ALP –

pH

Answer 2

pH 9.0-10.0

Question 3

Gastric enzyme – pH

Answer 3

pH 6.0

Question 4

For each ?°C increase in temp. reaction rate doubles

until the protein is denatured

Answer 4

10

Question 5

– should always be provided in excess so that the extent of the reaction does not depend on its concentration

Answer 5

Cofactors

Question 6

What are measured in measurement of enz activity? (4)

Answer 6

INC in product
DEC in substrate
DEC in coenzyme
INC in altered coENZ

Question 7

In coupled ENZ assay,

-what catalyzes its reaction, product formed becomes a substrate of intermediate reaction.

Answer 7

enzyme under analysis

Question 8

In coupled ENZ assay,

-what produces an intermediate product that will be the substrate for the final reaction

Answer 8

Intermediate auxiliary enzyme

Question 9

What absorbs light at 340 nm while NAD does not)

Answer 9

NADH

Question 10

Usually involves the conversion of NAD to NADH or vice versa [what enzyme type in coupled ENZ)

Answer 10

indicator enzyme

Question 11

catalyzes the final reaction

Answer 11

indicator enzyme

Question 12

method for couple ENZ assay

measures single absorbance at fixed time, reaction is assumed to be linear over fixed time

Answer 12

fixed time

Question 13

method for couple ENZ assay

multiple absorbances are measured

Answer 13

Continuous monitoring/kinetic assay

Question 14

method for couple ENZ assay

more accurate because any deviation from linearity is readily observed

Answer 14

Continuous monitoring/kinetic assay

Question 15

*most common cause of deviation from linearity

Answer 15

occurs when the enzyme is so elevated that all substrate is used early in the reaction time

Question 16

Units to report enzyme levels when enzymes are quantified relative to
their activity rather than a direct measurement of concentration

Answer 16

Activity Units

Question 17

amount of enzyme that will catalyze the reaction of 1umol of substance per minute under specified conditions

Answer 17

IU

Question 18

Enzyme activity SI unit –

Answer 18

katal (mol/s)

Question 19

How many nkat is in 1.0IU?

Answer 19

1.0 IU = 17nkat

Question 20

When will enz act as REAGENTS

Answer 20

measure non enzymatic constituents like glucose, cholesterol

Question 21

Enzymes as __

Used for methods quantifying substrates for the corresponding enzyme

Answer 21

Reagent

Question 22

– chemically bonded to adsorbents such as agarose

Answer 22

Immobilized Enzyme

Question 23

Systematic name of CK

Answer 23

Creatine-N-phosphotransferase

Question 24

MW of CK

Answer 24

82000 Daltons

Question 25

ENZ assoc with ATP regeneration

Answer 25

CK

Question 26

Creatine + ATP (catalyzed by CK) will yield

Answer 26

creatine phosphate + ADP

Question 27

minor tissue sources of CK

Answer 27

bladder, placenta, GIT, thyroid, uterus, kidney, lung, prostate, spleen, liver, pancreas

Question 28

CK levels are elevated in (3)

Answer 28

MI Rhabdomyolysis Muscular dystrophy

Question 29

CK isoenz – brain type, migrates fastest to the anode

Answer 29

CK-BB

Question 30

CK isoenz | Cannot pass blood-brain barrier, undetectable in blood

Answer 30

CK-BB

Question 31

CK isoenz | Elevated in patients with various carcinomas; may be useful tumor associated marker

Answer 31

CK -BB

Question 32

– hybrid type, less than 6% of total CK

Answer 32

CK-MB

Question 33

CK-MB – hybrid type, less than ?% of total CK

Answer 33

6

Question 34

are more sensitive markers of MI; they are released earlier and persist longer

Answer 34

Troponin I and T

Question 35

CK Isoenz Following myocardial infarction, levels rise within 4-8 hours, peak at 12-24 hours, and return to normal after 48-72 hours

Answer 35

CK-MB

Question 36

CK isoenz | – muscle type, most common, migrates slowest to the anode

Answer 36

CK-MM

Question 37

atypical ck – migrates midway between CK- MM and CK-MB

Answer 37

Macro-CK

Question 38

atypical ck | CK-MM complexed with IgG, or CK-MM complexed with lipoproteins

Answer 38

Macro-CK

Question 39

atypical ck | In serum, 0.8-1.6%

Answer 39

Macro-CK

Question 40

atypical ck | Age and sex related

Answer 40

Macro-CK

Question 41

atypical ck | – bound to exterior surface of the inner mitochondrial membranes of muscle, brain, and liver cells

Answer 41

Mitochondrial CK (CK-MI)

Question 42

enzyme released from hemolyzed RBCs and appearing as a band cathodal to CK-MM

Answer 42

adenylate kinase

Question 43

may cause falsely elevated CK or CK-MB value

Answer 43

adenylate kinase

Question 44

– more sensitive and precise than electrophoresis if done properly

Answer 44

Ion-exchange chromatography

Question 45

ref mtd of isoenz meas

Answer 45

EF

Question 46

– measure enzyme concentration rather than enzymatic activity,

Answer 46

Immunoassays (Radioimmunoassay, immunoinhibition)

Question 47

mtd of isoenz meas | can detect inactive forms of enzymes

Answer 47

Immunoassays (Radioimmunoassay, immunoinhibition)

Question 48

CK MEAS | Tanzer Gilvarg coupled with

Answer 48

PK-LD-NADH system

Question 49

CK MEAS | Tanzer Gilvarg pH

Answer 49

9.0

Question 50

CK meas | Oliver Rosalki coupled with

Answer 50

HK-G-6-NADP system

Question 51

CK meas | Oliver Rosalki pH

Answer 51

6.8

Question 52

Tanzer gilvarg | ADP + ____◄PK► pyruvate + ATP

Answer 52

phosphoenolpyruvate

Question 53

Tanzer gilvarg | ADP + phosphoenolpyruvate ◄PK► __ + ATP

Answer 53

pyruvate

Question 54

Tanzer gilvarg | Pyruvate + NADPH + H+ ◄LD► ____ + NAD+

Answer 54

Lactate

Question 55

CK meas | 2 to 6 times faster than forward reaction

Answer 55

Oliver Rosalki

Question 56

Oliver Rosalki Creatine phosphate + __◄CK► creatine +___

Answer 56

Creatine phosphate + ADP ◄CK► creatine | +ATP

Question 57

Oliver Rosalki | ATP + __ ◄HK► ADP + ___

Answer 57

ATP + glucose ◄HK► ADP + G-6-P

Question 58

Oliver Rosalki | __ + NADH ◄G-6-PD►__ + NADPH

Answer 58

G-6-P + NADH ◄G-6-PD► 6- phosphogluconate + NADPH

Question 59

CK errors | ___ mg/dL hemoglobin interferes

Answer 59

>320

Question 60

Errors in CK meas | Instability of CK – rapid inactivation of enzyme due to oxidation of ___ group

Answer 60

sulfhydryl

Question 61

Errors in CK meas Instability of CK Can be partially reversed by adding

Answer 61

sulfhydryl compounds: N- acetylcysteine, mercaptoethanol, thioglycerol, dithiotreitol

Question 62

– inactivates CK

Answer 62

Light exposure

Question 63

Light exposure inactivates CK Activity can be restored if specimen is (2)

Answer 63

1) stored in the dark at 4°C/7 days | 2) 20°C/month if the assay used a sulfhydryl activator

Question 64

higher muscle mass results in __ CK levels

Answer 64

higher

Question 65

RR of ck M

Answer 65

15-160 U/L

Question 66

RR of ck F

Answer 66

15-130 U/L