Enzymes Flashcards
Which blood group has increased intestinal ALP after consumption of a fatty meal?
B or O blood group
A nonspecific liver function test
Alkaline Phosphatase
True or False: Bone ALP is not normally elevated in children and geriatric patients.
False. It is normally found in healthy serum of pediatric and geriatric patients.
Major tissue sources of ALP.
Liver, Bone, Placenta and Intestine
Specific enzyme classification of ALP.
Hydrolase (Esterase)
Most abundant phosphatases.
Bone and Liver ALP
High ALP, high GGT. Diagnosis?
Obstructive Jaundice.
High ALP, normal GGT. Diagnosis?
Paget’s Disease (Osteitis deoformans)
Primary test for obstructive jaundice.
Alkaline Phosphatase
Secondary test for obstructive jaundice.
Gamma Glutamyl Transamine Peptidase
Bone ALP isoform detected in serum of dialysis patients.
B1x
B1x, a bone ALP isoform, is used to study what disease?
Low Bone Mineral Disease
Carcinoplacental ALP that rises in cases of breast, ovarian and gynecological cancers.
Regan ALP
Regan ALP migrates with what ALP isoenzyme?
Bone ALP
Which ALP isoenzyme is inhibited by phenylalanine?
Placental, Intestinal, Regan and Nagao ALP
Which ALP isoenzyme is inhibited by levamisole?
Bone and Liver ALP
Which ALP isoenzyme is inhibited by 3M urea?
Bone ALP
Which ALP isoenzyme is inhihited by L-leucine?
Nagao ALP
Carcinoplacental ALP found in adenocarcinoma of pancreas and bile duct and pleural cancer.
Nagao ALP
What reagent inhibits Nagao ALP?
Phenylalanine and L-leucine
What reagent inhibits bone ALP?
Levamisole and 3M urea
Most anodal ALP isoenzyme.
Liver ALP
Least anodal ALP isoenzyme.
Intestinal ALP
What reagents improve the isolation of ALP isoenzymes in electrophoresis?
Neuraminidase and wheat germ lectin
Arrange ALP isoenzyme from most anodal to least anodal.
Liver ALP
Bone ALP
Placental ALP
Intestinal ALP
It is a test performed at 56 C for 10 to 15 minutes to differentiate heat stability of ALP isoenzymes.
Heat Fractionation Test or Heat Stability Test
Most heat stable ALP isoenzyme.
Placental ALP
Most heat labile ALP isoenzyme.
Bone ALP
This method uses different concentrations of phenylalanine, synthetic urea and levamisole solutions.
Chemical Inhibition Test
Other name for Bowers and Mc Comb Method.
Szasz modification
Considered as the most specific method for ALP.
Bowers and Mc Comb
Substrate used in Bowers and Mc Comb and Bessy, Lowry and Brock.
a. For what enzyme?
b. End product?
c. End color?
p-nitrophenyl phosphate
a. ALP
b. p-nitrophenol or nitrophenoxide ion
c. Yellow
What is the enzyme activator of ALP?
Magnesium
What will be the effect of hemolysis and fatty meals in serum ALP?
Falsely elevated
True or False: ALP is sensitive if stored at low temperature and leads to decreased serum level.
False. It will lead to increased serum level.
What is the purpose of 2-amino-2-methyl-1-propanol (AMP) buffer in Bowers-McComb method?
Binds phosphorus that may inhibit ALP
What is the buffer added to bind the phosphorus in order to avoid ALP inhibition?
2-amino-2-methyl-1-propanol (AMP)
Level of ALP in zinc deficiency.
Decreased
ALP isoenzyme that is a useful tumor marker in serum and CSF for most germ cell tumors.
Placental ALP
Prolonged ______ levels of ALP occur in hypophosphatasia.
low or decreased
ACP activity >50 IU/L indicates the presence of what body fluid in the sample?
Seminal fluid
Tissue sources of ACP.
Prostate (major) RBCs Platelets Liver Bone
Ideal pH for ACP reaction.
pH 5.0
Diagnostic significance of ACP.
a. Detection of prostatic adenocarcinoma
b. Forensic clinical chemistry (rape cases)
How long can seminal fluid ACP persist in vaginal washings?
7 days
ACP methodology commonly used.
Roy and Hillman
Substrate used in Roy and Hillman? For what enzyme?
Thymolphthalein monophosphate
ACP
With acidification, ACP is stable for how many days at room temperature?
2 days
This inhibits prostatic ACP.
20mM L-tartrate ions
These inhibit red cell ACP.
1mM cupric sulfate and 2% formaldehyde ions
Tartrate-Resistant Acid Phosphatase (TRAP) is present in what disease?
Hairy Cell Leukemia
What is used together with prostatic acid phosphatase to monitor recurrence of prostate cancer?
Prostate Specific Antigen (PSA)
Specific enzyme classification of ACP.
Hydrolase (Esterase)
Substrates and products of AST.
Substrate: aspartate and alpha-keto acids
Products: oxaloacetate and glutamate
2 isoenzyme fractions of AST?
Cytoplasm and Mitochondrial AST
Major tissue sources of AST.
Cardiac tissue, liver and skeletal muscle.
Other: kidney, pancreas and RBC
Rise, peak and normal of AST in AMI.
Rise: 6-8 hours
Peak: 24 hours
Normal: within 5 days
Used for monitoring therapy with potentially hepatotoxic drugs.
AST (3x above normal limit may mean cessation of therapy)
Method used in AST determination.
Karmen method
pH and wavelength in Karmen Method.
pH 7.5 at 340 nm
Other enzyme used in Karmen method aside from AST.
Malate dehydrogenase
In myocardial infarction, hepatocellular disorders and skeletal muscle involvement, AST is _________.
a. decreased
b. increased
c. normal
d. cannot be determined
b. increased
Substrates and products of ALT.
Substrates: alanine and alpha-ketoglutarate
Products: glutamate and pyruvate
Specific liver enzyme test.
ALT
Major tissue source of ALT.
Liver
Other tissue sources of ALT aside from liver.
Kidney Pancreas RBC Heart Skeletal muscles Lungs
Enzyme used to screen blood donors.
ALT
Sensitive and specific screening test for posttransfusion hepatitis and occupational toxic exposure
ALT
Method for ALT.
Couple enzymatic reaction
Reitman and Frankel
Cofactor of aminotransferases.
Pyridoxal phosphate (vitamin B6)
Disease that causes highest elevation of transferases.
Acute hepatitis
Disease that produces elevations of transferase up to 20x the normal limits.
Viral and toxic hepatitis
Increased: ALP, ALT, AST, Bilirubin (both)
Normal: TPAG
Diagnosis?
Acute injury (Hepatitis) or Necrosis
Secondary markers for acute hepatitis and necrosis.
Increased LDH 4 and 5
Increased: ALP, Bilirubin (B2)
Slightly increased: ALT, AST
Normal: TPAG
Diagnosis?
Biliary Tract Obstruction (Obstructive Jaundice)
Secondary markers for obstructive jaundice.
Increased GGT, LAP and 5’NT
Increased: bilirubin (both), Globulin (IgA)
Slightly increased/decreased: ALT, AST, ALP
Decreased: TPA
Diagnosis?
Cirrhosis
Secondary markers for cirrhosis.
Increased NH3 and slightly increased or normal LDH 4 and 5
This enzyme catalyzes te breakdown of starch and glycogen.
Amylase
It is the smallest enzyme in size.
Amylase
It is the earliest pancreatic marker.
Amylase
What are the amylase isoenzymes?
Ptyalin (S-type)
Amylopsin (P-type)
True or False: Both ptyalin and amylopsin are present in normal sera.
True
Major tissue sources of amylase.
Acinar cells of the pancreas and the salivary glands
Other tissue sources of amylase.
Adipose Tissue
Fallopian tubes
Small intestine
Skeletal muscles
Most anodal amylase isoenzyme.
Ptyalin
What do you call the pancreatic amylase?
Amylopsin
What do you call the salivary amylase?
Ptyalin
Rise, peak and normal of amylase in acute pancreatitis.
Rise: 2-12 hours
Peak: 24 hours
Normal: within 3-5 days
In acute pancreatitis, increased AMS blood levels are accompanied by increased urinary excretion. How long does amylase stay elevated in urine?
Up to 7 days
Increased plasma amylase, decreased urinary amylase.
Diagnosis?
Renal failure
What is the expected amylase level in parotitis?
Increased
Samples with high activity of AMS shiuld be diluted with what?
NaCl (to prevent inactivation)
Morphine and other opiates will cause falsely _______ serum AMS levels.
Elevated
Substrate for all amylase methodologies.
Starch
Reference method of amylase determination. (State also the units used)
Saccharogenic (Somogyi units)
It measures the amount of reducing sugars produced by the hydrolysis of starch by the usual glucose methods.
Saccharogenic method (AMS)
It measures amylase activity by following the decreases in substrate concentration.
Amyloclastic
It measures amylase activity by the increase in color intensity of the soluble dye-substrate solution produced in the reaction.
Chromogenic
It measures amylase activity by a continuous-monitoring technique.
Coupled-enzyme
What inhibits salivary amylase?
Wheat germ lectin
AMS + immunoglobulin that is too large to be filtered across the glomerulus.
Macroamylasemia
Specific marker for acute pancreatitis.
Lipase
An enzyme that hydrolyzes the ester linkages of fats to produce alcohol and fatty acid.
Lipase
Major tissue source of lipase.
Pancreas
Rise, peak and normal of LPS in acute pancreatitis.
Rise: 6 hours
Peak: 24 hours, remains elevated for 7 days
Normal: 8-14 days
It is known as the late pancreatic marker.
Lipase
In general, what is the substrate used in lipase methodologies?
Olive oil or triolein
What needs to be added in order to make the lipase assay more sensitive and specific for acute pancreatitis detection?
Colipase and bile salts
The reference method for lipase determination.
Cherry Crandal
Substrate for Cherry Crandal.
50% olive oil or triolein
End product in Cherry Crandal assay.
2 fatty acids
Most commonly used method in lipase determination.
Peroxidase coupling
For what enzyme is the Tietz and Fiereck used as a methodology?
Lipase
Specific enzyme classification of AMS.
Hydrolase (Glucosidase)
An enzyme that catalyzes the interconversion of lactic and pyruvic acids.
Lactate dehydrogenase
Conenzyme of LD.
Nicotinamide dinucleotide (NAD+)
Two possible forms of LD.
H and M
In plasma, the majority of LD comes from breakdown of what?
Erythrocytes and platelets
Tissue sources of LD 1 and 2.
Heart muscles
RBC
Renal cortex
Tissue sources of LD 3.
Lungs
Spleen
Pancreas
WBC (lymphocytes)
Tissue sources of LD 4 and 5.
Liver
Skeletal muscles
Ileum
Skin
Highest serum levels of LD are seen in what diseases?
Pernicious anemia and hemolytic disorders
Rise and peak of LD in AMI.
Rise: 12-24 hours
Peak: 48-72 hours, elevated for 10-14 days
10-fold increase in LD signifies what disease?
Hepatic carcinoma and toxic hepatitis
LD that is 2 to 3 times higher that normal may be seen in _____________.
Viral hepatitis and cirrhosis
The flipped pattern (LD 1 > LD 2) is seen in what diseases?
Myocardial infarction
Hemolytic anemia
Renal infarction
LD cancer markers.
LD 2, LD 3 and LD 4
Physiologically, LD 1 is _______ LD 2.
a. lesser than
b. greater than
c. equal
d. NOTA
a. lesser than
The major LD isoenzyme in the sera of healthy persons.
LD 2
What does LD 6 represent?
Alcohol dehydrogenase
LD 6 is elevated in ____________.
Drug hepatotoxicity and obstructive jaundice
Heat stable LD isoenzyme.
LD 2
Most anodal LD isoenzyme.
LD 1
Least anodal and heat labile LD isoenzyme.
LD 4 and 5
More specific substrate for LD methodology.
Lactate
What is the forward or direct reaction in LD measurement?
a. pH and wavelength?
b. end product?
Wacker Method
a. pH 8.8 at 340 nm
b. NADH and pyruvate
What is the reverse or indirect reaction in LD measurement?
a. pH?
b. end product?
Wrobkeuski La Due
a. pH 7.2
b. NAD and lactate
For what enzyme determination is Wrobleuski Cabaud?
Lactate dehydrogenase
For what enzyme determination is Berger Broida?
Lactate dehydrogenase
Alternative substrate for LD measurement.
alpha-hydroxybutyrate
Transudates: ________ :: Exudates: _________.
a. high LD; high LD
b. low LD; low LD
c. low LD; high LD
d. high LD; low LD
c. low LD; high LD
Which analayte represents LD 1 activity and is elevated in conditions in which both the LD 1 and LD 2 are increased?
alpha-hydroxybutyrate dehydrogenase (alpha-HBD)
LD isoenzyme that is cold labile.
LD 5
This enzyme catalyzes the transfer of a phosphate group between creatine phosphate and adenosine diphosphate.
Creatine Kinase
This enzyme is involved in the storage of high-energy creatine phosphate in the muscles.
Creatine kinase
Twi different monomers of CK.
M and B
Major tissue sources of CK.
Brain tissue
Smooth and skeletal muscle
Cardiac muscle
Isoenzymes of CK and its tissue source.
CK BB (brain, muscles, prostate, kidney, thyroid, uterus and intestine) CK MB (heart muscle, tongue, esophagus) CK MM (heart and skeletal muscle)
Most anodal and labile CK isoenzyme.
CK 1
Major CK isoenzyme in sera of healthy persons.
CK MM
CK is a very sensitive indicator of what diseases?
Acute Myocardial Infarction and Duchenne disorder
Highest elevation of CK seen in?
Duchenne disorder
Rise, peak and normal of CK in AMI.
Rise: 4-8 hours
Peak: 12-24 hours
Normal: 48-72 hours
What is the forward or direct reaction in CK measurement?
a. pH and wavelength?
Tanzer-Gilbarg Assay
a. pH 9.0 at 340 nm
What is the reverse or indirect reaction in CK measurement?
a. pH and wavelength?
Oliver-Rosalki or Rosalki and Hess
a. pH 6.8 at 340 nm
Most commonly used method in CK determination.
Oliver-Rosalki
It is released after red cell lysis and causes interference in CK measuremeny because it is measured as CK by CK reagents.
Adenylate kinase
True or False: liver cells and RBC do nit contain CK.
True
Added to the reverse method in CK to inhibit AK.
Adenosine monophosphate (AMP)
CK activators.
Magnesium and N-acetylcysteine
Potent CK inhibitors.
Urate and cystine
Buffer used in CK measurement.
Imidazole
Partially restore lost activity of CK.
Cleland’s reagent and glutathione
True or False: CK is not sensitive to light but senstive to pH.
False. CK is sensitive to both light and pH.
Enzyme classification of creatine kinase.
Transferase
Enzyme classification of lactate dehydrogenase.
Oxidoreductase
Enzyme that splits fructose-1,6-diphosphate into two triose phosphate molecules in the metabolism of glucose.
Aldolase
Aldolase isoenzymes and its tissue source.
Aldolase A (skeletal muscles) Aldolase B (WBC, liver, kidney) Aldolase C (Brain tissue)
Enzyme cardiac markers according to its appearance in serum.
1st: CK-MB (4th hour)
2nd: AST (6th hour)
3rd: LD 1 and 2 (12th hour)
Enzyme skeletal muscle markers.
a. CK-MM
b. AST
c. Aldolase A
d. LD 4 and 5
Enzyme classification of 5’NT.
Hydrolase
This enzyme is a marker for hepatobiliary disease and infiltrative lesions of the liver.
5’ Nucleotidase
Dixon and Purdon, Campbell and Belfield and Goldberg are methodologies used in the measurement of what enzyme?
5’ Nucleotidase
This enzyme catalizes the transfer of glutamyl groups between peptides or amino acids through linksge at a gamma carboxyl group.
Gamma Glutamyl Transamine Peptidase
Elevated among individuals undergoing warfarin, phenobarbital and phenytoin therapies.
GGT
GGT is located in what?
Canaliculi of the hepatic cells Epithelial cell lining biliary ductules Kidney Prostate Pancreas
Substrate of GGT.
Gamma-glutamyl-p-nitroanilide
What are the methodologies for GGT determination?
Szass
Rosalki and Tarrow
Orlowski
Most alcohol sensitive enzyme.
GGT
Differrential test for the rise of ALP.
GGT
Most sensitive marker of acute alcoholic hepatitis.
GGT
Aside from alcoholism, GGT is also increased in what diseases?
Biliary tract obstructions
Pancreatitis
Prostatic disorders
This enzyme reflects synthetic function of the liber rather than injury.
Pseudocholinesterase
Acts as an antixenobiotic enzyme.
PChE. It catalyzes removal of benzyl group from cocaine
Marker for insecticide or pesticide poisoning.
Low serum PChE
Used to monitor effect of muscle relaxants (succinylcholine) after surgery.
PChE
It is involved in the metabolism of anticholinergic drugs.
PChE
Tissue source of PChE.
Liver
Myocardium
Pancreas
What is the diagnostically significant level of PChE.
Decreased. (Only enzyme)
Seen in acute hepatitis, cirrhosis, carcinoma metastatic to liver and malnutrition
Methodology used in the measurement of PChE.
Ellman Technique
Potentiometry
Other term for angiotensin-converting enzyme.
Pedtidyldipeptidase ir kininase II
Enzyme classification of ACE.
Hydrolase
This enzyme converts angiotensin I to angiotensin II within the lungs.
ACE
Enzyme that is a possible indicator of neuronal dysfunction (Alzheimer’s disease).
ACE
It is an enzyme that is the critical target for inhibitory drugs to lower blood pressure.
ACE
Tissue source of ACE.
Lungs
Testes
Macrophages
Epitheloid cells
Only protein with enzymatic activity.
Ceruloplasmin
Marker for Wilson’s Disease.
Ceruloplasmin
Enzyme marker for hepatobiliary disease.
Ornithine Carbamoyl Transferase (OCT)
This enzyme functions to maintain NADPH in the reduced form in the erythrocytes.
G6PD
A newborn sccreening enzyme marker.
G6PD
Tissue source of G6PD.
Adrenal cortex
Spleen
RBC
Lymph nodes
Deficiency of G6PD may lead to what disease after taking primaquine?
Drug-induced hemolytic anemia
G6PD is increased in what diseases?
Myocardial infarction
Megaloblastic anemia
Specimen for PChE measurement.
Serum or heparinized plasma
Specimen for G6PD measurement.
Red cell hemolysate and serum
Organic compounds essential to achieve absolute enzymatic activity. Second substrates.
Coenzymes
Inorganic ions which alters the spatial configuration of the enzyme for proper substrate binding.
Activators
General activators.
Calcium and potassium
LD activator.
Zinc
AMS activator.
Chloride
ALP and CK activator.
Magnesium
Inorganic ion attached to a molecule that must bind to enzyme before reaction occurs.
Metalloenzymes
Examples of metalloenzymes.
Catalase
Cytochrome oxidase
Enzymatic reaction may not progress if this interferes with the reaction.
Inhibitor
Inhibitor that physically binds ti the active site of the enzyme. Reversible.
Competitive inhibitor
Remedy for competitive inhibition.
Increase substrate or dilute specimen
Inhibitor that does not compete with the substrate but look for areas other than the active site.
Non-competitive inhibitor
Serves as the binding site for non-competitive inhibitor.
Allosteric site
This inhibitor binds to the enzyme-substrate complex.
Uncompetitive inhibitor
These are enzymes having the same catalytic reactions but slightly different molecular structures.
Isoenzymes
Enzymes are active at which temperature?
25, 30 and 37
The optimum temperature for enzymatic activity.
37
Temperature where denaturation of enzymes occur.
40 to 50
Temperature where inactivation of enzymes occur.
60 to 65
What does Q10 mean?
For every 10C increase in temperature, there will be a two-fold increase in enzyme activity.
Most physiologic reactions of enzymes occur in what pH?
pH 7 to 8
Enzyme stored at room temperature.
LD (4 and 5)
Lactescense or milky specimen ________ enzyme concentration.
a. increases
b. decreases
c. does not change
d. zeroes out
b. decreases
Enzyme class that catalayzes the removal or addition of electrons (redox reaction).
Oxidoreductase
Enzyme class that catalyzes the transfer of a chemical group other than hydrogen from one substrate to another.
Transferase
Enzyme class that catalyzes the hydrolysis or splitting of a bond by the addition of water.
Hydrolase
Enzyme class that catalyzes the removal of groups from substrates without hydrolysis.
Lyases
Enzyme class that catalyzes the intramolecular arrangement of the substrate compound.
Isomerases
Enzyme class that catalyzes the joining of two substrate molecules, coupled with breaking of the pyrophosphate bond in ATP or similar compound.
Ligases
Diseases with pepsin deficiency.
Cystic fibrosis
Tissue source of trypsin.
Pancreas.
Tissue source of pepsin.
Stomach
Coenzyme that is bound tightly to the enzyme.
Prosthetic group
Apoenzyme + prosthetic group = ______________.
Holoenzyme
Digestive enzyme in its inactive form originally secreted from the organ of production.
Proenzyme or zymogen
The reaction rate depends only on enzyme concentration.
Zero-order reaction
The reaction rate is ditectly proportional to substrate concentration.
First-order reaction
1 micromole of substrate/minute.
International Unit (IU or U)
1 mole of substrate/second.
Katal Unit (KU)
