PHOSPHATASES Flashcards
ALKALINE PHOSPHATASE (ALP)
• E.C.
3.1.3.1
Systematic name of ALP
Orthophosphoric Monoester Phosphohydrolase (Alkaline optimum)
ALP function
Catalyzes hydrolysis of phosphomonoesters at alkaline pH
- Liberates inorganic phosphate from organic phosphate ester
ALP
• Produces an_____ as a byproduct
alcohol
ALP
Optimal pH
= 9.0 to 10.0
ALP
Activator:
Mg2+& Zinc
ALP reaction
Phosophomonoester -> Alcohol +
Phosphate ion
TISSUE SOURCE
ALKALINE PHOSPHATASE (ALP)
Highest Concentrations:
Intestine
Liver (sinusoidal and bile canalicular membranes)
Placenta
Bone (osteoblasts)
Spleen
Kidney
ISOENZYME ANALYSIS
ALKALINE PHOSPHATASE (ALP)
Electrophoresis
Heat stability
Chemical Inhibition
Abnormal reactions
Electrophoresis mnemonics ( I Promise 2 Be Loyal)
Intestinal
Placental
Bone
Liver
Heat stability (Promise Ikaw Lang Baby)
Placental
Intestinal
Liver
Bones
ALP
• Major isoenzymes:
intestine, liver, bone, placenta
most useful technique for isoenzyme analysis
Electrophoresis
ALP
ISOENZYMES fastest migration
Liver isoenzyme:
Liver isoenzyme: 2 types
Mother Fucker
Major liver band/fraction
Fast liver fraction (a1 liver)
Bone ALP
-increases due,to…
osteoblastic activity
BONE ALP normally elevated in…
children during periods of growth and in adults older than age 50
Intestinal ALP
-depends on the______ and ______ of the individual’
-increases after consumption of______
-bound by erythrocytes of “_____” group
-diseases of the_____ and _____
blood group and secretor status
fatty meal
A
digestive tract and cirrhosis
-chronic hemodialysis
Intestinal ALP
LIVER isoenzymes
- hepatobillary conditions
- metastatic carcinoma (obstructive liver disease)
Major liver fraction
Fast liver fraction
ISOENZYME ANALYSIS
ALKALINE PHOSPHATASE (ALP)
• Used to identify isoenzyme source
• ALP activity is measured before and after heating the serum at____ for____
Heat Stability
56°C
10 minutes
Residual activity <20% after heating:
bone phosphatase
Residual activity > 20% after heating:
liver phosphatase
: most heat stable
Placental ALP
Most heat labile
Bone
ISOENZYME ANALYSIS
ALKALINE PHOSPHATASE (ALP)
• Chemical Inhibition
Phenylalanine
3M urea
Levamisole
Leucine
” Phenylalanine
• inhibits (2)
intestinal, and placental ALP
Phenylalanine also inhibits the…
carcinoplacental isoenzyme
3M Urea
Inhibits ____ ALP
Bone
Levamisole
Inhibits (2) ALP
Bone and Liver
Leucine
Inhibits the…
Nagao isoenzyme
NEOPLASTIC ISOENZYMES
ALKALINE PHOSPHATASE (ALP)
Regan isoenzymes
Nagao isoenzymes
• carcinoplacental ALPs
Regan and Nagao isoenzymes
ALP Isoenzymes
migrates to the same position as the bone fraction
most heat stable of all ALP isoenzymes
Regan
ALP Isoenzyme found in lung, breast, ovarian, and colon cancers
Regan
variant of Regan isoenzyme
found in metastatic carcinoma and adenocarcinoma
Nagao
Associated with hepatoma and gastrointestinal tract
tumors
Kasahara
DIAGNOSTIC SIGNIFICANCE
ALKALINE PHOSPHATASE (ALP)
Significant in…
hepatobiliary and bone
disorders
T or F
ALP is more prominent in obstructive conditions than hepatocellular disorders
True
ALP
Observed with____ involvement in bone disorders
osteoblast
Hepatobiliary Disorders:
Biliary tract obstruction:
ALP levels 3 to
10 times the ULN
Hepatobiliary disorders
Hepatitis and cirrhosis: increases by..
slight increases
(usually <3 times the ULN)
DIAGNOSTIC SIGNIFICANCE
ALKALINE PHOSPHATASE (ALP)
• Bone Disorders:
Highest elevation seen in this condition
Paget’s disease
• Highest elevations in Paget’s disease (Osteitis deformans)
DIAGNOSTIC SIGNIFICANCE
ALKALINE PHOSPHATASE (ALP)
Other disorders:
osteomalacia,
rickets, hyperparathyroidism,
osteogenic sarcoma
Bone disorders
ALP
Elevated during ——-and periods of physiologic——-
healing bone fractures
bone growth
ALKALINE PHOSPHATASE (ALP)
“ Pregnancy:
• Increased ALP activity
(______at 16-20 weeks; _____ in third trimester)
• Returns to normal within ___after labor
1.5 times ULN
2-3 times ULN
3-6 days
DIAGNOSTIC SIGNIFICANCE
ALKALINE PHOSPHATASE (ALP)
Pregnancy:
Complications:
elevated in hypertension,
preeclampsia, eclampsia, and threatened abortion
DIAGNOSTIC SIGNIFICANCE
ALKALINE PHOSPHATASE (ALP)
Decreased ALP: inherited condition with subnormal ALP activity
Hypophosphatasia
DIAGNOSTIC SIGNIFICANCE OF ALP ISOENZYMES
ALKALINE PHOSPHATASE (ALP)
• Bone Isoenzyme:
• Increased due to_____ activity
• Elevated in…
osteoblastic
children during growth and adults over 50
DIAGNOSTIC SIGNIFICANCE OF ALP ISOENZYMES
ALKALINE PHOSPHATASE (ALP)
Intestinal Isoenzyme:
• Dependent on…
• Elevated after____, in digestive tract diseases, and chronic hemodialysis
blood group and secretor status
fatty meal
ASSAY FOR ENZYME ACTIVITY
ALKALINE PHOSPHATASE (ALP)
Continuous-Monitoring Technique:
Based on Bowers and McComb method
ALP
• Most specific method
Bowers and McComb method
Bowers and McComb
Calculates ALP activity using molar absorptivity of…
p-nitrophenol
Bowers and McComb
Substrate =
Positive result =
Optimal pH:
para Nitrophenylphosphate
(PNPP); colorless
Yellow (p-nitrophenol)
10.2
Bowers and McComb
Measurement:
Increase in absorbance at____
Absorbance directly proportional to____ activity
405 nm
ALP
SOURCE OF ERROR
ALKALINE PHOSPHATASE (ALP)
Hemolysis
Timing of assays
Dietary influences
SOURCE OF ERROR
ALKALINE PHOSPHATASE (ALP)
Hemolysis:
Can cause slight elevations in ALP levels
ALP concentration:
~6 times higher in erythrocytes than in
serum
SOURCE OF ERROR
ALKALINE PHOSPHATASE (ALP)
Timing of Assays:
ALP assays should be performed_____
Serum activity increases by _______when left standing at
__________
immediately after collection
3% to 10%
25°C or 4°C for several hours
SOURCE OF ERROR
ALKALINE PHOSPHATASE (ALP)
Dietary Influences:
Diet can induce elevations in ALP activity
Blood group ________ individuals who are secretors may show:
Up to_______ after consuming a_____
Blood group B and O
25% higher values
high-fat meal
NOMENCLATURE & FUNCTION
ACID PHOSPHATASE (ACP)
EC
Systematic name
E.C. 3.1.3.2
Orthophosphoric Monoester Phosphohydrolase (Acid Optimum)
ACP
• Optimal pH =
• Activator =
5.0
Magnesium & Zinc
TISSUE SOURCE
ACID PHOSPHATASE (ACP)
: Richest source, highest activity
Prostate
Prostate
ACP
• Other sources:
Bone, liver, spleen, kidney, erythrocytes, platelets
DIAGNOSTIC SIGNIFICANCE
ACID PHOSPHATASE (ACP)
•_________:
• Historically used for detecting metastatic carcinoma of the prostate
• Less sensitive than newer markers like _______
Prostatic Carcinoma Detection
Prostate-Specific Antigen (PSA)
Other Conditions with ACP Elevations:
Hyperplasia of the prostate
Prostatic surgery, rectal examination, and prostate massage (conflicting reports)
Other Conditions with ACP Elevations:
bone diseases: lagets disease, breast cancer with bone metastases,
Gauchers disease
ACP elevation
Forensic applications: Elevated ACP in _____as evidence of rape
vaginal washings
ACP Elevation Platelet damage: Elevations in_____ due tc excessive platelet destruction
thrombocytopenia
METHODS OF PROSTATIC ACP DETECTION ACID PHOSPHATASE (ACP)
• Chemical Inhibition
• Immunologic Techniques
METHODS OF PROSTATIC ACP DETECTION ACID PHOSPHATASE (ACP)
• Chemical Inhibition:
“ Uses substrates like______
Differentiates prostatic ACP using_____ inhibition
thymolphthalein monophosphate
tartrate
METHODS OF PROSTATIC ACP DETECTION ACID PHOSPHATASE (ACP)
• Equation:
• Not entirely specific, as lysosomal ACP is also inhibited by tartrate
Total ACP - ACP after tartrate inhibition = Prostatic ACP
ACP
Immunologic Techniques:
• Uses antibodies specific for prostatic ACP Improved sensitivity but not useful for screening non- metastasized cancer
ASSAY FOR ENZYME ACTIVITY
ACID PHOSPHATASE (ACP)
•
Substrate: Thymolphthalein monophosphate
Roy and Hillman (Quantitative Endpoint)
ASSAY FOR ENZYME ACTIVITY
ACID PHOSPHATASE (ACP)
Substrate:
• Babson, Read & Phillips (Continuous Monitoring)
• Substrate:
Thymolphthalein monophosphate
Alpha-naphthyl phosphate
ASSAY FOR ENZYME ACTIVITY
ACID PHOSPHATASE (ACP)
• Immunochemical Techniques for prostatic ACP:
• Radioimmunoassay (RIA)
• Counterimmunoelectrophoresis
• Immunoprecipitation
• Immunoenzymatic Assay (Tandem E)
Immunoenzymatic Assay (Tandem E):
• Incubates sample with an antibody to______
Followed by washing and incubation with______
________formed is measured photometrically and is proportional to prostatic ACP in the sample
prostatic ACP
p-nitrophenylphosphate
p-Nitrophenol
SOURCE OF ERROR
ACID PHOSPHATASE (ACP)
• Sample Handling:
• Serum should be separated from__________________ to prevent leakage of erythrocyte and platelet ACP.
red cells immediately after clotting
Sources of errors
ACP
Serum activity decreases within ______hours at______ if no preservative is added.
Decrease is due to CO2 loss and subsequent increase in pH.
1 to 2 hours; room temperature
ACP
To Prevent Decrease:
Freeze or acidify serum to a______
Acidified serum remains stable at
room temperature for up to______
pH < 6.5
2 days
Hemolysis:
• Avoid hemolysis as it leads to contamination with…
erythrocyte ACP
• RIA Procedures:
• Require_____ serum samples.
• Stable for up to____ at _____
nonacidified
2 days at 4°C.
REFERENCE RANGE
ACID PHOSPHATASE (ACP)
• Reference Range
• Prostatic ACP,_____
• Tartrate-resistant ACP
• adults:
children:
0 to 3.5 ng/mL
1.5-4.5 U/L (37°C)
3.5-9.0 U/L (37°C)