MAJOR CLINICAL ENZYMES Flashcards
A nonspecific phosphatase enzyme capable of reacting with many different substrates
Alkaline phosphatase
In healthy sera, ALP levels are derived from
Liver and Bone (osteoblasts)
Bone isoenzyme increases due to osteoblastic activity and normally elevated in
Children during periods of growth and geriatric adults
In normal pregnancy, increased ALP activity can be detected between
16-20 weeks of pregnancy
ALP is higher in individuals of what blood group?
Groups B and O
After consumption of a fatty meal intestinal ALP of B or O blood group what?
Increases
Placental ALP is lower in pregnant women of what blood group?
Groups A and AB
Major tissue sources of ALP
Liver, bone, placenta and intestinal
When total ALP levels are increased, it is the major liver fraction that is most frequently elevated, especially in what disease?
Obstructive Jaundice
For bone disorders, highest elevations of ALP occur in
Paget’s disease (osteitis deformans)
Cardioplacental ALP found in lung, breast, ovarian and gynecological cancers; Bone ALP co-migrator. Most heat stable ALP (65℃ for 30mins). Inhibited by phenylalanine reagent
Regan ALP
Found in adenocarcinoma of the pancreas and bile duct, pleural cancer; variant of Regan ALP; inhibited by L-leucine and phenylalanine
Nagao ALP
The most anodal ALP isoenzymes are
Liver and Bone ALPs
The least anodal ALP isoenzyme
Intestinal ALP
Improves separation of bone and liver ALPs in Electrophoresis
Use of neuraminidase and wheat germ lectin
Unheated serum
High ALP
Performed at 56℃ for 10 minutes
Heat Fractionation/Stability Test
Most heat stable ALP
Placental ALP
Most heat labile ALP
Bone ALP
Decreasing order of ALP heat stability
Placental, Intestinal, Liver and Bone
Inhibited by Phenylalanine reagent in Chemical Inhibition Test
Placental and Intestinal ALPs
Inhibited by 3M Urea
Bone ALP
Inhibited by Levamisole
Bone and Liver ALPs
Considered as the most specific method and IFCC recommended. A continuous monitoring technique which requires a pH environment of 10.15 and should be read at 450nm
Bowers and McComb (Szasz Modification)
Required pH environment for Bowers and McComb method
pH of 10.15
Bowers and McComb method should be read at
450nm
A component of ALP
Zinc
Enzyme activator for ALP
Magnesium
Sources of analytical errors; elevated serum ALP
Hemolysis and diet(fatty meals)
ALP is sensitive if stored at what temperature
Low temp (4℃)
If ALP is stored at 4℃ it would lead to
Increased serum level
ALP is inhibited by
Phosphorus
Decreased ALP is seen in
Zinc deficiency
Prolonged low levels of ALP occur in
Hypophosphatasia
Transient low serum ALP may occur after
Blood transfusion or cardiopulmonary bypass
A useful tumor marker in serum and CSF for most germ cell tumors
Placental ALP (PLAP)
Phosphatase enzyme active at pH 5.0
Acid Phosphatase
Indicates the presence of seminal fluid in the sample
ACP activity >50IU/L
Tissue sources of ACP
Prostate, RBCs, platelets, liver and bone (osteoclasts)
ACP is used for the detection of
Prostatic Adenocarcinoma/Metastatic Prostate Carcinoma
Useful in forensic clinical chemistry, in the investigation of rape cases
Acid Phosphatase
Seminal fluid-ACP activity examined in vaginal washings can persists for up to how many days
4 days
Serum ACP decreases within how many hours if left at room temperature?
1 to 2 hours
If not assayed immediately serum for ACP tests should be
Frozen or acidified to a pH lower than 6.5
With acidification, ACP is stable for how many days at room temperature?
2 Days
ACP inhibited by 20mM L-tartarate ions
Prostatic ACP
ACP inhibited by 1mM cupric sulfate and 2% formaldehyde ions
Red Cell ACP
Present in certain chronic leukemias and some lymphomas, most notably hairy cell leukemia
Tartarate-resistant acid phosphatase (TRAP)
ACP in thrombocytopenia
Increased ACP
Markers used to monitor recurrence of prostate cancer
Prostatic acid phosphatase (PAP) & Prostate specific antigen (PSA)
Marker that is more sensitive in detecting stages A and B prostatic cancer
PSA - Prostate Specific Antigen
Transferase/transminase enzyme involved in the transfer of an amino group between aspartate and alpha keto acids with the formation of oxaloacetate and glutamate
Asparate Aminotransferase (AST)
Other name of AST
Serum glutamate-oxaloacetic transaminase (SGOT)
In AMI, AST levels begin to rise
6-8 hours
In AMI, AST levels peak at
24 hours
In AMI, AST levels normalize within
5 days
Method for AST that uses malate dehydrogenase (MD) and monitors the change in absorbance at 340nm
Karmen Method
Highest concentration is in the liver, more liver-specific than AST
Alanine Aminotransferase (ALT)
Other name of ALT
Serum glutamate-pyruvic transaminase (SGPT)
Major tissue source of ALT
Liver
Other tissue sources of ALT
Kidney, pancreas, RBC, heart, Skeletal muscles, lungs
Significant in the evaluation of hepatic disorders and markedly increased concentration in acute inflammatory conditions than AST
ALT
Normal in Myocardial Infarction
ALT
Used to screen blood donors
ALT levels
More sensitive and specific screening test for posttransfusion hepatitis or occupational toxic exposure
ALT
Aminotransferases are present in
Human plasma, bile, CSF and saliva
Error that should be avoided because it increases AST 10x
Hemolysis
Anticoagulant that may inhibit the activity of AST (but not all methods)
Heparin
The highest elevations of transferase is seen in what hepatitis?
Acute Hepatitis
In acute hepatitis, the De Ritis Ratio (ALT:AST) is
> 1.0
Transferase level in chronic hepa, hepatic cancer and IM is
Moderately elevated
Transferase level in hepatic cirrhosis, alcoholic hepatitis and obstructive jaundice
Slightly increased
ALT levels in Obstructive Jaundice
Slightly increased
ALT levels in Necrotic Jaundice
Markedly increased
With most forms of acute hepatocellular injury, such as hepatitis this transferase enzyme will be higher initially because of the higher activity in hepatocytes
AST
Within 24-48 hours, particularly if ongoing damage occurs, this transferase enzyme will become higher based on its longer half-life
ALT
The levels of both enzymes generally are not elevated and may be low as the result of massive tissue destruction
End-stage cirrhosis
An enzyme that catalyzes the breakdown of starch and glycogen
Amylase
An important enzyme in the physiologic digestion of starch
Amylase
Earliest pancreatic marker
Amylase
The most predominant pancreatic amylase isoenzyme in acute pancreatitis
P3
Amylase isoenzyme predominantly in normal serum
S-type (ptyalin)
Amylase isoenzyme predominantly in urine
P-type (amylopsin)
Major tissue source of Amylase
Acinar cells of the pancreas and salivary glands
In Acute Pancreatitis, AMS levels rise
2-12 hours after onset of attack
In AP, AMS levels peak at
24 hours
In AP, AMS levels normalize within
3-5 days
Anticoagulant that may inhibit the activity of AMS using some but not all methods
Heparin
Lipid classification that may inhibit serum AMS activity
Triglycerides
Samples with high activity of AMS should be diluted with what to prevent inactivation
Sodium Chloride (NaCl)
Administration of these drugs before blood sampling would lead to falsely elevated serum AMS levels
Morphine and other opiates
Administration of morphine and other opiates for pain relief before blood sampling will lead to
Falsely elevated serum AMS levels
Substrate for all methods of AMS
Starch
Classic reference method expressed in Somogyi units
Saccharogenic
Measures the amount of reducing sugars produced by the hydrolysis of starch by the usual glucose methods
Saccharogenic
Measures amylase activity of following the decrease of starch
Amyloclastic
Measures amylase activity by the increase in color intensity
Chromogenic
Measures amylase activity by a continuous-monitoring technique
Coupled-enzyme
The most specific pancreatic marker-secreted exclusively in the pancreas; not affected by renal disorders
Lipase
Substrates for LPS assay
Olive oil and Triolein
Reference method for LPS
Cherry Crandal
Most commonly used method; does not use 50% olive oil
Peroxidase coupling
Earliest Pancreatic Marker
Amylase
Most specific pancreatic marker
Lipase
In AP, LPS levels rise
6hrs after onset of attack
In AP, LPS levels peak at
24hrs
In AP, LPS levels remain elevated for
7 days
In AP, LPS levels normalize in
8-14 days
