Enzymes

Question 1

What are enzymes?

Answer 1

biological catalysts that increase rxn without changing/consuming
they alter the rate but not chemical equalibrium

Question 2

T/F: catalyze reactions are specific and essential to things such as DNA synthesis and energy

Answer 2

true

Question 3

T/F: without enzymes, the body could still function normally, probably

Answer 3

false

Question 4

what are cofactors?

Answer 4

also called activators, non-protein substances essential for enzyme activity (INORGANIC)
Ex: Mg, Cl, K, Zn

Question 5

What are Coenzymes?

Answer 5

organic substances loosely binded to protein, participate but not substrate
Ex. NADH, dehydrogenase (ORGANIC)

Question 6

Apoenzyme definition

Answer 6

protein portion of an enzyme

Question 7

holoenzyme definition

Answer 7

the complete, active enzyme complex (apoenzyme w coenzyme)

Question 8

T/F: Zymogen is the inactivated secreted form of an enzyme

Answer 8

true

Question 9

What are prosthetic groups?

Answer 9

tightly bound non-protein molecules

Question 10

Active site

Answer 10

where substance is acted on substrate, specificity

Question 11

What is an allosteric site?

Answer 11

cavity other than the active site, may also bind with enzyme

Question 12

T/F: the Enzyme substrate complex is bound non covalently

Answer 12

true

Question 13

What is another name for the ES complex?

Answer 13

adduct

Question 14

What do oxldoreductases do?

Answer 14

transfer hydrogen and oxygen atoms from one substrate to another

Question 15

what do transferases do?

Answer 15

transfer specific group from one enzyme to another

Question 16

what do hydrolases do?

Answer 16

hydrolysis of a substrate

Question 17

what do isomerases do?

Answer 17

change the molecular form of substrate

Question 18

what do lyases do?

Answer 18

nonhydrolytic removal or addition of a group to substrate

Question 19

what to ligases do?

Answer 19

joining of two molecules to form a new bond

Question 20

What are some enzyme reaction conditions?

Answer 20

temperature specific
Temp/pH most at body temp. NO HIGHER THAN 40 c (this denatures the protein)

Question 21

T/F: at -5 c enzymes are inactivated and can be stored

Answer 21

true

Question 22

Substrate concentration: concentration of an enzyme with steadily increasing concentration of substrate refers to which order?

Answer 22

first order kinetics

Question 23

T/F: concentration is not a rate limiting step

Answer 23

false it is limiting

Question 24

What is another name for excess substrate?

Answer 24

post zone phenomenon

Question 25

Describe the transition state

Answer 25

substance is converted to a product, must reach a higher level of free energy to convert substrate to product

Question 26

T/F: by lowering the activation energy the transition state can be easily overcome

Answer 26

true

Question 27

T/F: When determining enzyme concentration- enzyme concentration must always exceed the substrate concentration

Answer 27

FALSE

Question 28

Describe zero order kinetics. What is excess called?

Answer 28

reaction where an active site of an enzyme is saturated with substrate. Excess --> pro zone phenomena

Question 29

T/F: in the michalis menten curve, the 1st order is directly proportional to amount of substrate

Answer 29

true

Question 30

What is Km in the michalis menten curve

Answer 30

reaction velocity is half of maximum level

Question 31

T/F: you must over come first order to get to zero order

Answer 31

true

Question 32

T/F: line weaver burk plot is a more accurate Vmax and Km than MM?

Answer 32

true

Question 33

What is competitive inhibition?

Answer 33

compound shares structural similarities, binds and competes w substrate

Question 34

What is non competitive inhibition?

Answer 34

associate w places other than the active spot, allows substrate binding, inhibits products

Question 35

what is uncompetitive inhibition?

Answer 35

binds to enzyme substrate complex, doesnt allow products

Question 36

What is the hook effect?

Answer 36

high concentration altered and false low signals, too high is no longer accurate

Question 37

Aminotransferases: AKA transaminises, catalyze the transfer of amino groups to form AST and ALT found in all major organ tissues

Answer 37

just wanted one nice one you dont have to answer :)

Question 38

what is the functional unit of the liver? Cells present?

Answer 38

liver lobular, has hepatocytes that create proteins and help detox

Question 39

describe AST, location..etc

Answer 39

primary in heart and skeletal tissues intracellular --> cytoplasm/mitochondria short half life AVOID HEMOLYSIS

Question 40

T/F: AST is almost always lower than ALT

Answer 40

true

Question 41

AST ref range ALT ref range

Answer 41

5-35 Ul/L 7-45 Ul/L

Question 42

Describe ALT, location...etc

Answer 42

liver and kidney tissues found in cytoplasm less concentrated intracellularly so hemolysis isnt as bad as AST

Question 43

T/F: ALT is a predictor of liver damage, viral hepatitis, fatty liver and hepatitis drug abuse

Answer 43

true

Question 44

What are the coupled assay enzymes used in AST vs ALT?

Answer 44

AST --> malate ALT --> lactate

Question 45

describe ALP briefly, what is catalyzes, activators...etc

Answer 45

catalyzes alkaline pH isoforms specific to locations of body liver > bone> intestine MAGENSIUM ACTIVATOR yellow colo

Question 46

T/F: for ALP you should use citrate, oxalate, or EDTA

Answer 46

false, they can cause false increases in testing

Question 47

What is acid phosphotase?

Answer 47

pH below 7.0 prostate, liver..etc used for metastatic prostate carcinoma

Question 48

Briefly describe GGT

Answer 48

found in cell membrane and cytoplams secondary to hepatobility increased in pt with alcoholism/drugs normal in preggos and bone disorders

Question 49

What is the functional unit of pancreatic enzymes?

Answer 49

pancreatic ductal cells

Question 50

What are acinar cells? Centroacinar cells?

Answer 50

acinar --> zygo. granules, precursors to lipase and amylase Centroacinar cells --> create fluid in bicarb ions (alkaline)

Question 51

What are the two isoezymes of amylase and briefly define them

Answer 51

S-amylase: secreted by salivary glands p-amylase: secreted by pancreatic acinar cells

Question 52

Ref range of amylase

Answer 52

23-85 Ul/L

Question 53

T/F: high carbs, potatoes and rice cause high amylase T/F: as amylase decreases it is more probably for pancreatitis

Answer 53

true for both

Question 54

Acute pancreatitis: amylase activity after 5 to 8 hrs and only in heparinized plasma, what is the lab protocol take away?

Answer 54

NAD+ ---> NADH thats it lol

Question 55

Lipase reference range

Answer 55

0-160 Ul/L

Question 56

T/F: lipase levels can stay elevated for 14 days

Answer 56

true

Question 57

Lactate dehydrogenase ref range and 5 isoenzymes

Answer 57

ref: 140 -280 Ul/L iso enzymes LD1-LD5

Question 58

Order of lactate dehydrogenase enzymes in normal pt vs when AMI is present

Answer 58

LD2>LD1>LD3>LD4>LD5 norm LD1>LD2 with AMI (acute myocardial infarction)