Enzymes Flashcards
What are enzymes?
biological catalysts that increase rxn without changing/consuming
they alter the rate but not chemical equalibrium
T/F: catalyze reactions are specific and essential to things such as DNA synthesis and energy
true
T/F: without enzymes, the body could still function normally, probably
false
what are cofactors?
also called activators, non-protein substances essential for enzyme activity (INORGANIC)
Ex: Mg, Cl, K, Zn
What are Coenzymes?
organic substances loosely binded to protein, participate but not substrate
Ex. NADH, dehydrogenase (ORGANIC)
Apoenzyme definition
protein portion of an enzyme
holoenzyme definition
the complete, active enzyme complex (apoenzyme w coenzyme)
T/F: Zymogen is the inactivated secreted form of an enzyme
true
What are prosthetic groups?
tightly bound non-protein molecules
Active site
where substance is acted on substrate, specificity
What is an allosteric site?
cavity other than the active site, may also bind with enzyme
T/F: the Enzyme substrate complex is bound non covalently
true
What is another name for the ES complex?
adduct
What do oxldoreductases do?
transfer hydrogen and oxygen atoms from one substrate to another
what do transferases do?
transfer specific group from one enzyme to another
what do hydrolases do?
hydrolysis of a substrate
what do isomerases do?
change the molecular form of substrate
what do lyases do?
nonhydrolytic removal or addition of a group to substrate
what to ligases do?
joining of two molecules to form a new bond
What are some enzyme reaction conditions?
temperature specific
Temp/pH most at body temp. NO HIGHER THAN 40 c (this denatures the protein)
T/F: at -5 c enzymes are inactivated and can be stored
true
Substrate concentration: concentration of an enzyme with steadily increasing concentration of substrate refers to which order?
first order kinetics
T/F: concentration is not a rate limiting step
false it is limiting
What is another name for excess substrate?
post zone phenomenon
Describe the transition state
substance is converted to a product, must reach a higher level of free energy to convert substrate to product
T/F: by lowering the activation energy the transition state can be easily overcome
true
T/F: When determining enzyme concentration- enzyme concentration must always exceed the substrate concentration
FALSE
Describe zero order kinetics. What is excess called?
reaction where an active site of an enzyme is saturated with substrate.
Excess –> pro zone phenomena
T/F: in the michalis menten curve, the 1st order is directly proportional to amount of substrate
true
What is Km in the michalis menten curve
reaction velocity is half of maximum level
T/F: you must over come first order to get to zero order
true
T/F: line weaver burk plot is a more accurate Vmax and Km than MM?
true
What is competitive inhibition?
compound shares structural similarities, binds and competes w substrate
What is non competitive inhibition?
associate w places other than the active spot, allows substrate binding, inhibits products
what is uncompetitive inhibition?
binds to enzyme substrate complex, doesnt allow products
What is the hook effect?
high concentration altered and false low signals, too high is no longer accurate
Aminotransferases: AKA transaminises, catalyze the transfer of amino groups to form AST and ALT found in all major organ tissues
just wanted one nice one you dont have to answer :)
what is the functional unit of the liver? Cells present?
liver lobular, has hepatocytes that create proteins and help detox
describe AST, location..etc
primary in heart and skeletal tissues
intracellular –> cytoplasm/mitochondria
short half life
AVOID HEMOLYSIS
T/F: AST is almost always lower than ALT
true
AST ref range
ALT ref range
5-35 Ul/L
7-45 Ul/L
Describe ALT, location…etc
liver and kidney tissues
found in cytoplasm
less concentrated intracellularly so hemolysis isnt as bad as AST
T/F: ALT is a predictor of liver damage, viral hepatitis, fatty liver and hepatitis drug abuse
true
What are the coupled assay enzymes used in AST vs ALT?
AST –> malate
ALT –> lactate
describe ALP briefly, what is catalyzes, activators…etc
catalyzes alkaline pH
isoforms specific to locations of body
liver > bone> intestine
MAGENSIUM ACTIVATOR
yellow colo
T/F: for ALP you should use citrate, oxalate, or EDTA
false, they can cause false increases in testing
What is acid phosphotase?
pH below 7.0
prostate, liver..etc
used for metastatic prostate carcinoma
Briefly describe GGT
found in cell membrane and cytoplams
secondary to hepatobility
increased in pt with alcoholism/drugs
normal in preggos and bone disorders
What is the functional unit of pancreatic enzymes?
pancreatic ductal cells
What are acinar cells?
Centroacinar cells?
acinar –> zygo. granules, precursors to lipase and amylase
Centroacinar cells –> create fluid in bicarb ions (alkaline)
What are the two isoezymes of amylase and briefly define them
S-amylase: secreted by salivary glands
p-amylase: secreted by pancreatic acinar cells
Ref range of amylase
23-85 Ul/L
T/F: high carbs, potatoes and rice cause high amylase
T/F: as amylase decreases it is more probably for pancreatitis
true for both
Acute pancreatitis: amylase activity after 5 to 8 hrs and only in heparinized plasma, what is the lab protocol take away?
NAD+ —> NADH thats it lol
Lipase reference range
0-160 Ul/L
T/F: lipase levels can stay elevated for 14 days
true
Lactate dehydrogenase ref range and 5 isoenzymes
ref: 140 -280 Ul/L
iso enzymes LD1-LD5
Order of lactate dehydrogenase enzymes in normal pt vs when AMI is present
LD2>LD1>LD3>LD4>LD5 norm
LD1>LD2 with AMI
(acute myocardial infarction)
