(F) L1: Enzymes (Part 2) Flashcards
Major Clinical Enzymes: Phosphatases
- Aka “Alkaline Orthophosphoric Monoester Phosphohydrolase”
- Is non-specific
- Is active in a pH of 10 to 15
- It liberates inorganic phosphate with a byproduct of alcohol
Alkaline Phosphatase (ALP)
Alkaline Phosphatase
What are the 5 major tissue sources of ALP?
- Liver
- Bone
- Placenta
- Intestine
- Kidney
Alkaline Phosphatase
Order the tissue sources from most abundant to least abundant:
- Placenta
- Intestine
- Liver
- Bone
- Kidney
- Liver (major source)
- Bone (major source)
- Placenta
- Intestine
- Kidney (minor source)
Alkaline Phosphatase
An increase in bone isoenzyme is seen in what 2 age groups?
- Growing children
- Geriatric patients (>50 years old)
For children, since they are continuously undergoing bone resorption, bone tissues are continuously destroyed which liberates the enzymes
Alkaline Phosphatase
An increase in ALP can also be seen in pregnant women how many weeks along in their pregnancy?
16-20 weeks
Alkaline Phosphatase
ALP is affected by an individual’s blood type (choose among ABO):
- Increase in intestinal isoenzyme after a fatty meal
- Decrease in intestinal isoenzyme after a fatty meal
- Decrease in placental isoenzyme for pregnant women
- B and O
- A and AB
- A and AB
Alkaline Phosphatase
What is the reference value?
30-90 U/L
Subjected to changes depending on multiple factors such as age, sex, race, and others
Alkaline Phosphatase
What are the 4 major clinical isoenzymes?
- Placental ALP
- Intestinal ALP
- Liver ALP
- Bone ALP
Alkaline Phosphatase (Specimen Considerations)
Match the elements with their functions:
1. One of the major components of ALP
2. An activator required in the analysis
3. An inhibitor
A. Phosphorus
B. Zinc
C. Magnesium
- B
- C
- A
Alkaline Phosphatase (Specimen Considerations)
In order to bind and inhibit phosphorus (since it is already a normal serum component), what buffer must be used?
2-amino-2-methyl-1-propanol (AMP)
Alkaline Phosphatase (Specimen Considerations)
Does ALP increase or decrease after these activities/events?
- Hemolysis
- After ingestion of fatty meals (or food in general)
- Sample stored at 4ºC
Note: Fasting is not required for ALP testing
Increase
Alkaline Phosphatase (Methods of Analysis)
This separates the different isoenzymes of ALP since each type exhibits different migrating patterns
Electrophoresis
Alkaline Phosphatase (Electrophoresis)
What is/are the most anodal and least anodal isoenzymes?
Choose between: Liver, Bone, and Intestinal
- Most anodal = Liver and Bone
- Least anodal = Intestinal
Alkaline Phosphatase (Electrophoresis)
What is Neuraminidase and Wheat Germ Lectin’s role in electrophoresis?
Separating agents for the separation of bone and liver ALP
Alkaline Phosphatase (Electrophoresis)
High resolution electrophoresis using polyacrylamide gel with isoelectric focusing is used for what purpose?
To separate multiple overlapping ALP bands
Alkaline Phosphatase (Methods of Analysis)
This exposes enzymes at 56ºC for 10-15 minutes wherein the most stable enzyme will persevere
Heat Fractionation/Stability Test
Alkaline Phosphatase (Heat Fractionation/Stability Test)
Rank the ALPs from most heat stable to most heat labile?
Choices: Bone, Placenta, Intestinal, and Liver
Placental, Intestinal, Liver, Bone
Alkaline Phosphatase (Methods of Analysis)
Uses chemical reagents at different concentrations to inhibit the different isoenzymes of ALP
Chemical Inhibition Test
Alkaline Phosphatase (Chemical Inhibition Test)
- Inhibits placental and intestinal ALP
- Inhibits liver and bone ALP
A. Levamisole
B. Synthetic or 3M Urea
C. Phenylalanine
- B and C
- A
Alkaline Phosphatase (Methods of Analysis)
- The most specific method for ALP analysis (recommended by IFCC)
- It measures however the total ALP amount and not the specific isoenzymes
- It incorporates the concept of absolute specificity
- A kinetic method that requires continuous monitoring at 405nm between a pH of 10 to 15
- It reacts p-nitrophenylphosphate (PNPP) with ALP to produce p-nitrophenol and phosphate ions
Bowers and McComb (Szasz Modification)
Diagnostic Significance of Alkaline Phosphatase
In cases of obstructive jaundice, ALP secretion in what organ is increased which leads to an increase in the total ALP?
Liver
When subjected under electrophoresis, the liver isoenzyme band may be increased
Diagnostic Significance of Alkaline Phosphatase
In patients with Paget’s disease or osteotitis deformans, ALP secretion in what organ is increased?
Bone
Diagnostic Significance of Alkaline Phosphatase
Patients who have undergone blood transfusion and cardiopulmonary bypass may exhibit a transient (increase/decrease) in ALP which will return to normal after some time
Decrease
Diagnostic Significance of Alkaline Phosphatase
What ALP is increased in the ff. patients?
- Dialysis patients
- Patients with low bone mineral disease (BMD) of the hips
- Those with chronic kidney disease
B1x isoform (modified bone ALP)
Diagnostic Significance of Alkaline Phosphatase
A prolonged (increase/decrease) in ALP is seen in patients with hypophosphatasia
Decrease
Abnormal Forms of Alkaline Phosphatase
- Seen in lung, breast, ovarian, and gynecological cancer
- It is a co-migrator of bone ALP, wherein they are seen in the same place when subjected under electrophoresis
- The most heat stable, surviving at 65ºC for 30 minutes
- Is inhibited by phenylalanine
Regan ALP
Abnormal Forms of Alkaline Phosphatase
- Seen in patients with adenocarcinoma of the pancreas and bile duct, and pleural cancer
- A variant of Regan ALP
- It is inhibited by L-leucine and phenylalanine
Nagao ALP
Abnormal Forms of Alkaline Phosphatase
- Mirrors the placental ALP
- Seen in serum and CSF specimens of patients with germ cell tumors
- Determination of this is useful in differentiating pinealoma and germ cell tumor
Placental-like Alkaline Phosphatase (PLAP)
Abnormal Forms of Alkaline Phosphatase
Placental-like Alkaline Phosphatase (PLAP) is increased in patients with a (pinealoma/germ cell tumor)
Germ Cell Tumor
Major Clinical Enzymes: Phosphatases
- Aka “Acid Orthophosphoric Monoester Phosphohydrolase”
- Catalyzes the same reaction with ALP except that this is acid-loving
- Is maintained at a pH of 5 to 6
- Is mainly measured for male clinical chemistry, but not limited to it
Acid Phosphatase (ACP)
Acid Phosphatase (ACP)
An unknown specimen having ACP levels of greater than 50 U/L may be determined as having what fluid mixed in with the specimen?
Seminal fluid
Acid Phosphatase (ACP)
Arrange the tissue sources of ACP from most to least abundant:
- Platelets
- Liver
- Prostate gland
- RBCs
- Bones
- Prostate gland
- RBCs
- Platelets
- Liver
- Bones
Acid Phosphatase (ACP) Reference Values for Males
Determine if for Total ACP or Prostatic ACP:
1. 2.5 to 11.7 U/L
2. 0 to 3.5 ng/ml
- Total ACP
- Prostatic ACP
Acid Phosphatase (ACP) Specimen Considerations
- Sample should be free of hemolysis since it may lead to a falsely (increased/decreased) value of ACP as RBC can also be the source of the enzyme
- A/an (increase/decrease) in the levels of ACP is seen when the sample is left at room temperature for 1 to 2 hours
- Increased
- Decrease
Acid Phosphatase (ACP) Specimen Considerations
This serves as the specific substrate for a quantitative endpoint reaction
Thymolphthalein monophosphate
Acid Phosphatase (ACP) Specimen Considerations
This substance may also be used when using an enzymatic kinetic method which requires continuous monitoring
A-naphthyl phosphate
Acid Phosphatase (ACP) Specimen Considerations
If the sample won’t be assayed immediately, it may be subjected to the following:
1. (Freezing/Refrigeration)
2. Acidification to a pH lower than 6.5 to make it stable for (two/three) days at room temperature
- Freezing
- Two (2)
Acid Phosphatase (ACP) Specimen Considerations
These serve as inhibitors for prostatic ACP
20mmol of L-tartrate ions
Acid Phosphatase (ACP) Specimen Considerations
This serves as an inhibitor for RBC ACP
1mmol of cupric sulfate + 2% formaldehyde
Acid Phosphatase (ACP) Diagnostic Significance
ACP is mainly used in males for the detection of what?
Note: The number of ACP increases due to an increase in the number of cells when diagnosed with this
Prostatic adenocarcinoma
Acid Phosphatase (ACP) Diagnostic Significance
ACP levels fall (faster/slower) than the prostate specific antigen (PSA) in cases of surgical treatment
Faster
PSA is mainly concerned with immunology rather than CC
Acid Phosphatase (ACP) Diagnostic Significance
ACP determination is also useful for rape cases wherein vaginal washings are examined for seminal fluid ACP which can persist for up to how many days?
4 days
Acid Phosphatase (ACP) Diagnostic Significance
This is a form of ACP that is resistant to L-tartrate and a known inhibitor of prostatic ACP, which is seen in chronic and hairy cell leukemia
Tartrate Resistant Acid Phosphatase (TRAP)
Acid Phosphatase (ACP) Diagnostic Significance
Increased or Decreased ACP?
- Urinary tract obstruction
- Acute urinary retention
- Extensive prostatic massage
- Prostatic inflammation
- Infarction or Ischemia
- Prostatic manipulations (e.g. needle biopsy and cytoscopy)
- Prostatic carcinoma
- Breast, lung, and thyroid carcinoma
- Gaucher’s disease
- Niemann Pick disease
- Thrombocytopenia
Increased
Major Clinical Enzymes: Transferases/Transaminases
Aspartate and α-ketoacid reacts with this enzyme which will catalyze the transfer of an amino group to produce oxaloacetate and glutamate
Aspartate Aminotransferases or Serum Glutamic Oxaloacetic Transaminase (AST/SGOT)
Major Clinical Enzymes: AST/SGOT
What are the 3 major tissue sources of AST?
- Cardiac (major)
- Liver
- Skeletal (minor)
Other sources: Kidney, Pancreas, and RBCs