front 1 What is the definition of: Enzyme | back 1 reduces the activation energy of a reaction. Acts as a catalyst. (The Lock) a protein that decreases the activation energy of a reaction |
front 2 What is the definition of: Isoenzyme | back 2 :specific form of an enzyme, different isoenzymes can perform the same exact function, they just look a little different, or they may go about it in a slightly different manner. (The color of the lock, or how the lock looks) |
front 3 What is the definition of: Cofactor | back 3 : non-protein molecule necessary for enzyme activity (Tumblers inside the lock) - inorganic and organic compounds that are required for full enzyme function |
front 4 What is the definition of: Holoenzyme | back 4 The complete form of a functional enzyme unit complete with cofactors (Lock with the tumblers) |
front 5 What is the definition of: Apoenzyme : | back 5 The enzyme portion of a Holoenzyme, may or may not be active (The casing around the lock. looks like a lock, but does it lock? an inactive enzyme without its cofactor |
front 6 What is the definition of: Coenzyme : | back 6 an organic cofactor, AKA prosthetic group. (The metal key guard that you rotate to the side to insert the key) - organic cofactors that commonly have a structure related to vitamins |
front 7 What is the definition of: Oxidoreductases | back 7 - Oxidize or Reduce substrates |
front 8 What is the definition of: Transferases - | back 8 Transfer side groups (e.g. NH 3 ) between substrates |
front 9 What is the definition of: Hydrolases - | back 9 Add water to break apart a substrate |
front 10 What is the definition of: Lyases | back 10 - Breaks apart chemical bonds of a substrate |
front 11 What is the definition of: Isomerases | back 11 - Interconvert between forms of a substrate (think transforming) |
front 12 What is the definition of: Ligases | back 12 - Join together two organic substrates into one |
front 13 Under what classification is thyroid peroxidase considered in a reaction which oxidizes iron? | back 13 Oxidoreductase |
front 14 What is the summed up equation for enzyme. | back 14 S + E → ES → E + P |
front 15 What is the primary function of enzymes? | back 15 To reduce the activation energy of a reaction. This will subsequently increase the likelihood that this reaction will occur, and the amount of product that is being formed. |
front 16 What is the definition of zero order kinetics? | back 16 All of the enzyme binding sites are full and the enzyme is working at maximum capacity. A further increase in substrate concentration will NOT be able to increase the reaction speed. |
front 17 What type of inhibition can be overcome by an increase in substrate concentration? | back 17 Competitive inhibition |
front 18 What is the unit which we measure enzyme activity? | back 18 International Units |
front 19 CYP450 Phase I metabolism has what predominant effect on drugs? | back 19 Simple reactions like hydroxylation, oxidation, or reduction to make the drug more water soluble. |
front 20 A 23-year-old male living in Arizona is given a bottle of Ketoconazole for a coccidioidomycosis infection. He is also taking Phenytoin for his epilepsy that he has had since childhood. Ketoconazole is known to inhibit CYP450 enzymes in the liver. What effect would the addition of Ketoconazole likely result in for this patient? A. Cause increased phenytoin activity | back 20 The correct answer is D) This is caused because it
is |
front 21 Where do we want to measure enzyme concentration at on the
Michaelis-Menten curve? | back 21 The correct answer is D) . When we have |
front 22 A patient’s enzyme kinetic assay is interpreted by your lab and you
see the Lineweaver-Burk plot. It appears that the patient has an
inhibitor to the enzyme in question. This inhibitor has decreased just
the Vmax, but not the K m . What is the inhibitor type? | back 22 The correct answer is C) . The total Vmax is decreased, which
basically means that the inhibitor renders the bound enzyme obsolete
in catalyzing the reaction. Noncompetitive inhibitors bind to sites on
the enzyme other than the active site for the substrate, therefore,
they do not compete for the binding site. When
these |
front 23 A male bodybuilder has an elevated Total CK value. Is this expected? | back 23 Yes, CK is positively correlated with muscle mass. |
front 24 What is the subunits for: LD-1 | back 24 HHHH heart, RBCs, kidney. Are elevated in heart attacks |
front 25 What is the subunits for:LD-2 | back 25 HHHM lungs, RBCs |
front 26 What is the subunits for:LD-3 | back 26 HHMM spleen, lungs, and many tissues |
front 27 What is the subunits for:LD-4 | back 27 HMMM liver and skeleton |
front 28 What is the subunits for:LD-5 | back 28 MMMM liver and skeleton |
front 29 What is the primary tissues and High-Yield defects which cause elevation for the following isoenzyme:LD-1 | back 29 Primary tissues: Heart, RBCs High-Yield defects which cause elevation: Myocardial infarction, hemolytic anemia |
front 30 What is the primary tissues and High-Yield defects which cause elevation for the following isoenzyme:LD-2 | back 30 Primary tissues: Heart, RBCs High-Yield defects which cause elevation: Myocardial infarction |
front 31 What is the primary tissues and High-Yield defects which cause elevation for the following isoenzyme:LD-3 | back 31 Primary tissues: Lung, Lymphocytes, Pancreas High-Yield defects which cause elevation: Acute pancreatitis, pneumonia |
front 32 What is the primary tissues and High-Yield defects which cause elevation for the following isoenzyme:LD-4 | back 32 Primary tissues: Liver High-Yield defects which cause elevation: Hepatic injury |
front 33 What is the primary tissues and High-Yield defects which cause elevation for the following isoenzyme:LD-5 | back 33 Primary tissues: Liver, Skeletal Muscle High-Yield defects which cause elevation: Hepatic injury, skeletal muscle injury |
front 34 Edwin, a 42-year-old software engineer, falls into his double bacon cheeseburger, fries, and a shake at lunch and is unresponsive. He has no pulse and is rushed to the ER where he is diagnosed with a myocardial infarction. What would his LD isoenzymes look like? | back 34 His LD isoenzyme panel would show the 1,2 Flip. LD-1 is higher than LD-2. This is a stereotypical pattern for patients with myocardial infarctions. |
front 35 What are the 4 tissues that have the highest LD concentrations? | back 35 Kidney, Liver, Muscle, and RBCs |
front 36 What is a common cause of elevated AST in a normal patient? | back 36 Hemolysis in the tube |
front 37 What tissue is ALT found in primarily? | back 37 Liver |
front 38 A 15-year-old African boy is taking medications after he was diagnosed with malaria last week. He now has hemolytic anemia. What genetic deficiency does he likely have? | back 38 G6PD deficiency |
front 39 A 47-year-old anxious, obese female is complaining of shortness of
breath. She has had a strange sensation in her upper abdomen which
woke her up from sleep 3 days ago. She is concerned about the
possibility of gastric ulcers. From her online research over the past
3 days, she learned about this scary thing called ulcerative colitis
and thinks she has it. While these both could be possible, the astute
ER physician rapidly orders a CK-MB which comes back as slightly
elevated, but not alarming at all. What assay could her physician
order to help determine if she had a heart attack almost 4 days
ago? | back 39 The correct answer is B) Other cardiac biomarkers that would help out
in this scenario would be any of the troponins, Tn-I, Tn-C, or Tn-T.
Remember that these biomarkers stay elevated for a long time after the
other acute biomarkers have dropped off in concentration. Tn elevates
quickly and remains elevated for a long time, that makes this marker
the most specific marker when we are trying to determine a distant
heart attack. LD can come from many sources, so it is not as specific
to the heart. |
front 40 A 28-year old female comes into the ED and is confused. She is
afebrile, floridly jaundiced and unaccompanied by any of her family or
friends. Upon further questioning, the patient reveals a family
history of lupus, Graves’ disease, autoimmune hepatitis, and type 1
diabetes. She said that she was at a bar with her friends, but does
not remember how she got to the hospital. The ED physician gets the
following results from the tests ordered: | back 40 The correct answer is B) There’s a lot going on in this
question, |
front 41 A 67-year-old male presents to the hospital via ambulance. He is brought to the hospital miraculously less than 2 hours after observers saw him go unconscious. He is slightly jaundiced. As the team began ruling out all life-threatening causes of his loss of consciousness, they order these tests with the following results: He is diagnosed with liver disease because of the timeline.
What would the LD isoenzyme electrophoresis show? | back 41 The correct answer is C) These isoenzymes are fairly specific |
front 42 Where is the ALP enzyme most prominent in the body? | back 42 Biliary tract, placenta, bone, kidney, liver |
front 43 A 57-year-old male patient with benign prostatic hypertrophy and an elevated PSA has a total serum ACP value of 5 ng/mL. After tartrate inhibition, the serum ACP value dropped to 1 ng/mL. What is the total amount of prostatic ACP present? | back 43 4 ng/mL. 5 - 1 = 4. Remember, prostatic ACP is susceptible to tartrate. |
front 44 What is the greatest source of ACP in the human body? | back 44 Prostatic secretions |
front 45 A pregnant 28-year-old female has an elevated alkaline phosphatase.
What enzyme would tell the physician that the source of the ALP is NOT biliary? | back 45 If GGT were low, then that would rule-out a hepatobiliary source of the ALP |
front 46 AMY ( pancreatic amylase )has one job, what is it? | back 46 Destroy α-1, 4 glycosidic linkages |
front 47 How many free fatty acids are created from lipase, 12 triglycerides, and water? | back 47 24, 2 from every triglyceride and 12 monoglycerides |
front 48 A 44-year-old obese female who is the mother of 12 kids has episodic right upper quadrant abdominal pain after eating fatty meals. Lab results are as follows: What is the likely cause of her condition? | back 48 The correct answer is B) Gallstone (Choledocholithiasis). AST and ALT
will be elevated if there is liver damage so with this question stem,
I am really only thinking about answers A and B. Remember that ALP and
GGT are seen in extremely high concentrations in the bile ducts and
that they will be increased in just about any bile
duct |
front 49 A 62-year old male presents to the physician with groin pain. His
groin pain radiates into his back and points to where his kidneys are
located and is exacerbated when he jumps. It is not associated with
passive movement but he has noticed an inability to completely
evacuate his bladder upon urination. He has also noticed a dull,
painful sensation in his lower back and right anterior thigh. This
pain is associated with movement and is NOT always present.
Upon Where is the likely source of this patient’s medical
problem? | back 49 The correct answer is D) This is a long question stem with some great
clinical pearls hidden within the question stem. Let’s go through them
first and then we’ll go through the lab results. The groin pain
radiating to his back sounds like a musculoskeletal thing or
testicular torsion to me. The inability for complete evacuation of the
bladder during urination is a hallmark for benign prostatic
hypertrophy. We notice that this patient’s ALP is normal, so there is
likely not a skeletal disease causing this issue. Pain relief with
alcohol consumption is a typical finding. Alcohol not only dulls the
nerves which dulls the pain, it also dulls the neurons in your brain
to receive that pain. |
front 50 A 24-year-old female patient with pancreatitis presents to her
physician with weight loss, foul-smelling stool, jaundice, and
abdominal pain. What are the most likely pancreatic
enzymatic | back 50 The correct answer is D) This enzymatic deficiency causes
steatorrhea, which leads to what the experts call “foul-smelling
stool” (as if poop didn’t normally smell bad). The jaundice is often
caused by hepatocellular damage and inability to conjugate the
bilirubin to excrete it. The weight loss comes from the inability to
absorb fats. They’re all lost in the stool. We really only have one
enzyme that would cause all of these fat-related issues, LPS! A)
Amylase breaks down starches and carbohydrate chains. B) Glucagon is
released |
front 51 What is the definition of: Substrate - | back 51 the substance that is used up in the reaction |
front 52 What is the definition of: Product | back 52 - the substance that is formed in the reaction |
front 53 What is the definition of: Inhibitor | back 53 - a substance that prevents or inhibits a reaction from taking place |
front 54 What is the definition of: Kinetic assay | back 54 - the change of absorbance is measured on a spectrophotometer to assess the reaction rate . Have to do with speed |
front 55 What is the definition of: Endpoint assay - | back 55 the change in absorbance is measured at the end of the reaction. |
front 56 What is the definition of: International unit - | back 56 a unit of activity or potency for many substances defined individually in terms of the activity of a standard solution. |
front 57 What is the definition of: Vmax | back 57 - the maximum velocity of an enzymatic reaction |
front 58 What is the definition of: Km - | back 58 the concentration of substrate which allows the enzyme to achieve half Vmax |
front 59 What is the definition of: Activation energy - | back 59 the energy required to get the reaction started. Kind of like finding the energy required to get yourself off the couch on a lazy day |
front 60 What is the definition of: First order reaction - | back 60 The reaction rate is dependent upon substrate and enzyme concentrations |
front 61 What is the definition of: Zero order reaction - | back 61 The reaction rate is constant and dependent upon only the enzyme concentration |
front 62 What is the definition of: Prosthetic Groups | back 62 - coenzymes covalently bound to the enzyme |
front 63 What is the definition of: Holoenzyme | back 63 - is the apoenzyme and coenzyme in one catalytically active unit |
front 64 What is the definition of: Metalloenzyme | back 64 - enzymes that have a metallic ion in them |
front 65 What is the ratio for First Order Kinetics for the Michaelis-Menten Constant (Km) | back 65 - a 1:1 relationship between substrate and velocity |
front 66 What is Zero Order Kinetics - | back 66 the reaction reaches an asymptote, all enzyme sites are occupied and the reaction velocity cannot be increased by addition of substrate |
front 67 what is the Michaelis-Menten Constant (Km)? | back 67 is the substrate concentration at which the reaction rate is half of Vmax |
front 68 what should about Competitive inhibitor and Vmax and Km | back 68 Same Vmax different Km |
front 69 what should about noncompetitive inhibitor and Vmax and Km | back 69 Same Km Different vmax |
front 70 What does the Lineweaver Burk plots for competitive inhibition look like? | back 70 |
front 71 What does the Lineweaver Burk plots for noncompetitive(mixed) inhibition look like? | back 71 |
front 72 In healthy individuals what is the order of the isoenzymes for Lactate Dehydrogenase? | back 72 LD2 > LD1 > LD3 > LD4 > LD5 |
front 73 In Lactate Dehydrogenase what does Oxidoreductase do ? | back 73 catalyzes the conversion of L-lactate to pyruvate and NADH |
front 74 For LD methodology what is the Wacker procedure | back 74 |
front 75 For LD methodology what is the Wroblewski and LaDue reaction | back 75 |
front 76 What is the clinical significance of LD1>LD2 ? | back 76 “Flipped pattern” indicative of MI, shock, myocarditis, or CHF LD Peaks between 48 and 72 hours and stays elevated for 7-14 days |
front 77 What is the clinical significance of LD5>LD4 | back 77 Liver disease increases LD4 and LD5 |
front 78 What is important to know about LD reference ranges? | back 78 No clinically significant gender differences Ranges are significantly different based upon the method used Children have much higher LD values than adults Hemolysis causes a gigantic spike in the LD levels LD cannot be frozen! Activity is lost when frozen |
front 79 What are the four tissue types that have the highest LD concentrations? | back 79 Kidney, Liver, Muscle, and RBCs |
front 80 What are the refence ranges for Creatine Kinase (CK) in males? | back 80 = 52 - 236 U/L |
front 81 What are the refence ranges for Creatine Kinase (CK) in females? | back 81 38 - 176 U/L |
front 82 The conditions for CK to be stable are? | back 82 CK activity is unstable and lost during storage, light sensitive Only stable for 4 hours at RT, 48 hours at 4˚C, and 1 month at -20˚C |
front 83 The clinical significant of: CK-MB | back 83 It doesn’t peak for 24 hours. I t’s used to assess heart attacks |
front 84 The clinical significant of: CK-MM | back 84 It is elevated in Duchenne muscular dystrophy, seizures, trauma, and “extreme” exercise |
front 85 The clinical significant of: CK-BB | back 85 is elevated in brain injury, and is used as a tumor marker with Prostate and Small Cell Carcinoma of the lung |
front 86 In CK Electrophoresis where can CK1 = CK-BB be found? | back 86 travels the furthest |
front 87 In CK Electrophoresis where can CK2 = CK-MB be found? | back 87 travelest the 2nd furthest |
front 88 In CK Electrophoresis where can CK3 = CK-MM be found? | back 88 travels backward |
front 89 What is the most common reason for AST to be elevated in the blood of a normal patient? | back 89 Hemolysis in the tube |
front 90 in CK Isoenzyme Methodologies what is Immunoinhibition - | back 90 specific antibody against the CK-M subunit, old method and has been replaced by mass assay |
front 91 in CK Isoenzyme Methodologies what is a Mass assay | back 91 - Primary anti-M antibody Antibody attached to a solid phase, Then a labeled secondary anti-B antibody Signal is detected and directly proportional to CK-MB |
front 92 For CK Isoenzyme Reference Range. What CK-BB does indicate? | back 92 absent or trace amount |
front 93 For CK Isoenzyme Reference Range. What CK-MB does indicate? | back 93 ≤6% of total CK, ≥6% is a fairly specific indicator of MI, myocardial infarction |
front 94 For CK Isoenzyme Reference Range. What does CK-MM indicate? | back 94 94-100% |
front 95 For CK Isoenzyme Reference Range.Relative Index CK-MB (ug/L x 100) / total CK (U/L) indicate? | back 95 <3% = noncardiac source 4-5% = gray area >6% = cardiac source The greatest source of CK-MB in the normal serum is cardiac muscle |
front 96 What should you know about Aspartate Aminotransferase (AST)? | back 96 Catalyzes deamination Measured by the Karmen method. Think hemolysis and hepatitis Present in red blood cells, heart, liver, skeletal muscle, and kidney AST is the most sensitive enzyme to alcoholic liver injury |
front 97 The Aspartate Aminotransferase AST Reference Ranges are | back 97 Range at 37˚C is 5-30 U/L No clinically significant gender differences Hemolysis jeopardizes sample accuracy (because AST is found in high concentrations in RBCs) these are un acceptable for testing |
front 98 What should you know about Alanine Aminotransferase (ALT)? | back 98 Catalyzes the deamination Measured by the modified Wroblewski and LaDue method Uses Lactate Dehydrogenase as an indicator reaction Found primarily in the cytoplasm of cells Mostly a liver specific transaminase |
front 99 What is the clinical significance of Alanine Aminotransferase ALT? | back 99 DeRitis ratio (AST/ALT ratio) Alcoholic liver disease produces a ratio >2 s = s auced and l = l osing l iver Other hepatitis's can cause an AST/ALT ratio <1 |
front 100 The reference range for ALT? | back 100 Reference Range at 37˚C is 6-37 U/L Hemolysis jeopardizes sample accuracy |
front 101 Where can Acid Phosphatase ACP be found? | back 101 Osteoclasts , increases in bone disease, normal serum Prostate is the tissue with the highest concentration RBCs are have high intracellular concentrations Note: can’t be performed on a hemolysed sample |
front 102 What is Acid Phosphatase ACP Methodology? | back 102 Addition of tartrate inhibits Prostatic serum is derived from osteoclasts |
front 103 The purpose of Amylase (AMS) is | back 103 Hydrolase that catalyzes the hydrolysis of starches (breaks down starch into individual glucose molecules) 1.Salivary Amylase - secreted in the saliva, active at a pH of about 6.8 2.Pancreatic Amylase - secreted from the pancreas, active at the same pH |
front 104 Why do we need two types of virtually identical enzymes? | back 104 Increased in pancreatitis, alcoholism, parotitis Macroamylasemia, not medically interesting, but can cause hyperamylasemia SENSITIVE marker for pancreatitis Pancreatic amylase is activated by the chloride in gastric acid |
front 105 The purpose of lipase is? | back 105 Hydrolyzes glycerol esters to produce glycerol and free fatty acids Breaks down Triglyceride into 3 fatty acid chains and a gycerol back bone |
front 106 The clinical significance of lipase? | back 106 Produced by the Pancreatic Acinar Cells Peaks after 24 hours from the insult and remains elevated for 8-14 days SPECIFIC marker for pancreatitis |
front 107 What is the methodology for Lipase? | back 107 |
front 108 The reference ranges for lipase is? | back 108 Lipase is stable at RT for one week, 3˚C for 3 weeks, -20˚C for years |
front 109 The significance of Cholinesterase (CHE)? | back 109 deficiency for anesthesiologists because it causes patients to remain paralyzed for a prolonged period of time after neuromuscular blocking agents are given for surgery |
front 110 Cholinesterase Methodologies reference ranges for males are | back 110 40-78 U/L note :5-MNBA is measured at 410 nm |
front 111 Cholinesterase Methodologies reference ranges for females are | back 111 33-76 U/L note :5-MNBA is measured at 410 nm |
front 112 A man comes in to the clinic 4 days after a suspected heart attack. What is the best cardiac biomarker to order in this scenario? | back 112 Tn-I or Tn-T |
front 113 The markers for Myocardial Infarction are? | back 113 |
front 114 What is the mainstay for diagnosis of hepatitis? | back 114 AST and ALT note:ALT is more specific to liver tissue, whereas AST is found in many other tissues GGT and LD will also increase, but they are not commonly-tested in the setting of hepatitis |
front 115 The Tests that measure hepatocyte integrity are? | back 115
|
front 116 The Tests that measure hepatocyte function? | back 116
|
front 117 The Tests that assess the biliary tract? | back 117
|
front 118 What is Alkaline Phosphatase (ALP) associated with? | back 118 Associated with gallstones (choledocholithiasis) Refrigeration causes activity to decrease |
front 119 The formula for Bowers and McComb Reaction is? | back 119 |
front 120 A pregnant 28-year-old female has an elevated alkaline phosphatase. What enzyme would tell the physician that the source of the ALP is NOT biliary? | back 120 If GGT were low, then that would rule-out a hepatobiliary source of the ALP. |
front 121 The disease that is association with this enzyme malignancies is: ACP | back 121 Prostate Cancer |
front 122 The disease that is association with this enzyme malignancies is: ALP - ones | back 122 Lung, colon, ovarian, breast, uterine cancers, and lymphomas Possibly more to come, these are the high-yield |
front 123 Name the enzymes that you want to look for when you think the diagnosis could be pancreatitis? | back 123 1.Amylase 2.Lipase If these two enzymes are not elevated, then it’s going to be hard to convince anyone that the diagnosis is pancreatitis |
front 124 In Lineweaver-Burke Plots. what type of competition happens when: Lines cross on the Y, axis forming an X | back 124 Competitive inhibition, The Vmax is the same, which means Note: X intercept = -1/Km, Y intercept = 1/Vmax |
front 125 In Lineweaver-Burke Plots. what type of competition happens when: Lines meet at the X axis forming a V | back 125 Noncompetitive inhibition, The Km is the same and the Vmax is reduced, which means that
there Note: X intercept = -1/Km, Y intercept = 1/Vmax |
front 126 In Lineweaver-Burke Plots. what type of competition happens when: Lines do not cross, forming parallel lines | back 126 Uncompetitive inhibition, This inhibitor binds to the enzyme-substrate complex, therefore the
reaction has a very difficult time getting going at all. Both the Km
and Note: X intercept = -1/Km, Y intercept = 1/Vmax |
front 127 In Michaelis-Menten Curve what type of competition happens when: Km is increased, but Asymptote stays the same | back 127 Competitive inhibition The maximum velocity can still be reached, bit the note: Asymptote = Vmax, 1/2 Vmax = Km |
front 128 In Michaelis-Menten Curve what type of competition happens when: Asymptote is decreased, but Km stays the same | back 128 Noncompetitive inhibition The maximum velocity is decreased because there are less
active note: Asymptote = Vmax, 1/2 Vmax = Km |
front 129 In Michaelis-Menten Curve what type of competition happens when: Lines do not cross, forming parallel lines | back 129 Uncompetitive inhibition This inhibitor binds to the enzyme-substrate complex, therefore the
reaction has a very difficult time getting going at all. Both the Km
and note: Asymptote = Vmax, 1/2 Vmax = Km |
front 130 What does the Lineweaver Burk plots for uncompetitive inhibition look like? | back 130 |