LABS- 2nd semester

Question 1

what is the structure of lactate DH?

Answer 1

tetramer

Question 2

which LDH isoenzyme found in the heart?

Answer 2

LDH1

LDH2

Question 3

what is the location of LDH5?

Answer 3

liver

smooth muscle cell

Question 4

write down the reaction catalyzed by LDH-

Answer 4

pyruvate + NADH + H -> lactate + NAD

Question 5

what is the optimal lactate conc for LDH1 and LDH5?

Answer 5

LDH1= 10mM
LDH5= 250 mM

Question 6

what happens to LDH1 in the presence of 250mM lactate?

Answer 6

it is inhibited by 50%

Question 7

what is the different substrate specificity btw. LDH1 and LDH5?

Answer 7

LDH1= 2-oxobutyrate
LDH5= pyruvate

Question 8

which enzyme is fastest in the electric field separation method?

Answer 8

LDH1

Question 9

what is the prosthetic group of transaminase?

what is it derived from?

Answer 9

PLP

B6

Question 10

describe the reaction catalyzed by Asp-AT

Answer 10

Asp+aKG -> OAA+Glu

Question 11

where does Asp-AT localized?

where is it conc very high?

Answer 11

all organs

high conc in liver and heart

Question 12

describe the reaction catalyzed by Ala-AT

Answer 12

Ala+aKG -> pyruvate+Glu

Question 13

where does Ala-AT localized?

where is it activity very high?

Answer 13

liver- high activity
kidney
heart
skeletal m

Question 14

what is the reaction catalyzed by MDH (malate DH)?

Answer 14

OAA + NADPH +H -> malate + NAD

Question 15

in both experiments of ALAT and ASAT, what do we check?

Answer 15

we check the amount of NADH that was transfered to NAD (ill person is faster)

Question 16

in what disease does the levels of ASAT elevates more than ALAT?

Answer 16

myocardial infraction

Question 17

in what disease does the levels of ALAT elevates more than ASAT?

Answer 17

hepatocellular tissue destruction

remember, ALAT is with L, like the Liver

Question 18

write down the reaction catalyzed by creatine-kinase

Answer 18

ATP + creatine -> ADP + creatine-P + H

Question 19

where can we detect high amounts of creatine-kinase?

Answer 19

muscle
heart
brain

Question 20

what is the structure of creatine-kinase?

Answer 20

dimer (two subunits)

Question 21

describe the 2 subunits of creatine-kinase

what isoenzymes do they produce?\

Answer 21

CK-M
CK-B
produce 3 isoenzymes (CK-MM, CK-BB, CK-MB)

Question 22

connect each creatine-kinase isoenzyme to its organ

Answer 22

CK-MM: muscle
CK-BB: brain
CK-MB: heart

Question 23

which enzymes activity play a crucial role in the verification of myocardial infraction?

Answer 23

CK
LDH
LDH1
ASAT

Question 24

what is the normal range of fasting glucose levels?

Answer 24

3.5-5.5 mM

Question 25

in a healthy person, when can we see the highest blood glucos levels? (after a glucose load)

Answer 25

after 1 hour

Question 26

what value of fasting plasma glucose indicates diabetes?

Answer 26

more than 7mM

Question 27

what drug will inhibit Na/K ATPase?

Answer 27

Ouabain

Question 28

how can we determine the Na/K ATPase activity?

Answer 28

by assaying the amount of liberated inorganic phosphate using the Fiske-Subbarow colour reaction

Question 29

what is the perpose of biotransformation?

Answer 29

conversion of foreign (xenobiotics) compounds to water soluble substance excretion out of the body

Question 30

where does tthe CYP P450 localyzed?

Answer 30

in the ER membrane

Question 31

what happens in the CYP P450 system?

Answer 31

electrons are transfered from NADPH to FAD prosthetic group of CYP P450 reductase enzyme, and from FMNH2 electrons flow to CYP P450 hemoproetin to reduce ferric ion

Question 32

what does microsome contains?

Answer 32

plasma membrane ER membrane fragments (rich in CYP enzyme system)

Question 33

what is the most frequent reaction catalyzed by CYP P450?

Answer 33

hydroxylation

Question 34

give example of a compound that will induce many kinds of CYP isoenzymes?

Answer 34

polycyclic aromatic hydrocarbons

Question 35

what is aminophenazone? | what will happend to it?

Answer 35

antipyretic nonsteroidal anti-inflammatory drug | this compound will demethylated and will produce formaldehyde and free -NH2 remains on the drug

Question 36

what is the end product of blood coagulation?

Answer 36

fibrin gel

Question 37

what is the composition of fibrinogen? | how are they bound?

Answer 37

2Aa 2Bb 2gamma they are bound with disulfide bbonds

Question 38

what type of enzyme is the thrombin?

Answer 38

serine protease

Question 39

what does the thrombin cleave? | what is the product?

Answer 39

peptide bond in the Aa chain and the Bb chain | products are- fibrinopeptide A+B and fibrin I+II monomer

Question 40

what activates factor XIII? | what does it do?

Answer 40

thrombin glutamyl-lysyl amide cross links (isopeptide bond) btw a and gamma chains of the monomers

Question 41

what is the aim of the succinate DH lab?

Answer 41

determine whether malonate is a cometative inhibitor for succinate DH

Question 42

describe competative inhibitor | what happens to the Km?

Answer 42

binds reversibly to the free enzyme enzyme-inhibiroe has no catalytic activity Km increases

Question 43

write down the reaction catalyzed by succinate DH

Answer 43

succinate + FAD -> fumarate + FADH2

Question 44

why malonate can be succinate DH substrate analogue?

Answer 44

similar structure to succinate

Question 45

what is special about succinate DH?

Answer 45

it is the only inner mitochondrial membrane-bound enzyme of the citric acid cycle

Question 46

why do we use INT in the succinate DH experiment?

Answer 46

to make the reaction irreversible it is an artificial acceptor end product is red colored

Question 47

describe what is the P/O ratio

Answer 47

number of ATP synthesized per oxigen consumed

Question 48

what is special about the M-type pyruvate kinase?

Answer 48

(muscle) shows no allosteric behavior only under high ATP conc. it may be inhibited

Question 49

how did we measure the activity of pyruvate kinase in the lab?

Answer 49

rate of conversion of PEP to pyrubate is coupled to lactate DH. we measure the amount of NAD+ produced (pyruvate->lactate)

Question 50

which form absorbs the light in 340 nm? | NADH/NAD+

Answer 50

NADH

Question 51

how does pancreatic lipase activates?

Answer 51

colipase in the duodenum (pH dependant) alsombile acids enhance the activity of thr lipase enzymr (in the presebcr of colipase)

Question 52

describe the experiment of pancreatic lipase, what did we check?

Answer 52

lipase+colipase+milk | we compared results in the presence of water/presence of bile acids

Question 53

how did we evaluate the pancreatic lipase action?

Answer 53

value of NaOH required to neutralize the milk is directly related to the presence og TAG and hence the enzyme activity (we will see that is is hugher in the presence of bile acids)

Question 54

what is the cause for primary carnitine deficiency?

Answer 54

mutation un the gene coding OCTN2 that transports carnitine into cells

Question 55

in the laboratory practice the determination of the serum cholesterol level is assayed by the measurments of

Answer 55

formation of quinoneimin | (H2O2+phenol_amino-4-antipyrin->quinoneimine+2H2O catalyzed by peroxidase

Question 56

what are the enzymes that weree used in our experiment of determined serum TAG?

Answer 56

lipoproein lipase glycerol kinase glycerol-3-P-oxidase peroxidase

Question 57

what are the enzymes that weree used in our experiment of determined cholesterol?

Answer 57

cholesterol esterase cholesterol oxidase peroxidase

Question 58

what is the only inner mitochondrial membrane bound enzyme of the TCA? what is it competitive inhibitor?

Answer 58

succinate DH | malonate

Question 59

the reaction of succinate DH is measured by the following compound

Answer 59

reduced idonitrotetrazolium formazan which is red