CC LEC 2 - Enzymes Flashcards Preview

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Flashcards in CC LEC 2 - Enzymes Deck (66):
1

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

7.0- 8.0,

2

ALP –
pH

pH 9.0-10.0

3

Gastric enzyme – pH

pH 6.0

4

For each ?°C increase in temp. reaction rate doubles
until the protein is denatured

10

5

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

Cofactors

6

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

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

7

In coupled ENZ assay,
-what catalyzes its reaction, product formed becomes a substrate of intermediate reaction.

enzyme under analysis

8

In coupled ENZ assay,
-what produces an intermediate product that will be the substrate for the final reaction

Intermediate auxiliary enzyme

9

What absorbs light at 340 nm while NAD does not)

NADH

10

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

indicator enzyme

11

catalyzes the final reaction

indicator enzyme

12

method for couple ENZ assay
measures single absorbance at fixed time, reaction is assumed to be linear over fixed time

fixed time

13

method for couple ENZ assay
multiple absorbances are measured

Continuous monitoring/kinetic assay

14

method for couple ENZ assay
more accurate because any deviation from linearity is readily observed

Continuous monitoring/kinetic assay

15

*most common cause of deviation from linearity

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

16

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

Activity Units

17

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

IU

18

Enzyme activity SI unit –

katal (mol/s)

19

How many nkat is in 1.0IU?

1.0 IU = 17nkat

20

When will enz act as REAGENTS

measure non enzymatic constituents like glucose, cholesterol

21

Enzymes as __
Used for methods quantifying substrates for the corresponding enzyme

Reagent

22

– chemically bonded to adsorbents such as agarose

Immobilized Enzyme

23

Systematic name of CK

Creatine-N-phosphotransferase

24

MW of CK

82000 Daltons

25

ENZ assoc with ATP regeneration

CK

26

Creatine + ATP (catalyzed by CK) will yield

creatine phosphate + ADP

27

minor tissue sources of CK

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

28

CK levels are elevated in (3)

MI
Rhabdomyolysis
Muscular dystrophy

29

CK isoenz
– brain type, migrates fastest to the
anode

CK-BB

30

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

CK-BB

31

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

CK -BB

32

– hybrid type, less than 6% of total CK

CK-MB

33

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

6

34

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

Troponin I and T

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

CK-MB

36

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

CK-MM

37

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

Macro-CK

38

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

Macro-CK

39

atypical ck
In serum, 0.8-1.6%

Macro-CK

40

atypical ck
Age and sex related

Macro-CK

41

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

Mitochondrial CK (CK-MI)

42

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

adenylate kinase

43

may cause falsely elevated CK or CK-MB value

adenylate kinase

44

– more sensitive and precise than electrophoresis if done properly

Ion-exchange chromatography

45

ref mtd of isoenz meas

EF

46

– measure enzyme concentration rather than enzymatic activity,

Immunoassays (Radioimmunoassay, immunoinhibition)

47

mtd of isoenz meas
can detect inactive forms of enzymes

Immunoassays (Radioimmunoassay, immunoinhibition)

48

CK MEAS
Tanzer Gilvarg coupled with

PK-LD-NADH system

49

CK MEAS
Tanzer Gilvarg pH

9.0

50

CK meas
Oliver Rosalki coupled with

HK-G-6-NADP system

51

CK meas
Oliver Rosalki pH

6.8

52

Tanzer gilvarg
ADP + ____◄PK► pyruvate + ATP

phosphoenolpyruvate

53

Tanzer gilvarg
ADP + phosphoenolpyruvate ◄PK► __ + ATP

pyruvate

54

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

Lactate

55

CK meas
2 to 6 times faster than forward reaction

Oliver Rosalki

56

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

Creatine phosphate + ADP ◄CK► creatine
+ATP

57

Oliver Rosalki
ATP + __ ◄HK► ADP + ___

ATP + glucose ◄HK► ADP + G-6-P

58

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


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

59

CK errors
___ mg/dL hemoglobin interferes

>320

60

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

sulfhydryl

61

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

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

62

– inactivates CK

Light exposure

63

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

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

64

higher muscle mass results in __ CK levels

higher

65

RR of ck M

15-160 U/L

66

RR of ck F

15-130 U/L

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