ENZYMES OF CLINICAL SGNIFICANCE Flashcards
This catalyze interconversions of the amino acids and alpha-ketoaciddds by transfer of amino groups.
Aminotransferases
Give example of Aminotransferases.
Pyridoxal phosphate
What is the significance of Aminotransferases?
The products of the reaction of Aminotransferases enters the TCA. Therefore the main significant of AT is production of energy.
Which is the receiver in an Aminotransferase reaction?
Alpha-ketoacids
What is the function of Aminotransferases?
Amino acid metabolism
What cycle oxidized ketoacids?
TCA cycle
Transcribe SGOT
Serum Glutamic Oxaloacetic Transaminase
What is the reaction catalyzed of AST?
Aspartate + a-ketoglutarate <> Oxaloacetate + GLutamate
This is known to combine with Acetyl Coenzyme A particularly in the first step of the TCA cycle .
Oxaloacetate
What substance is Oxaloacetate known to combine with?
Acetyl Coenzyme A
What is the other importance of Oxaloacetate?
It is important in the biomolecule in Gluconeogenesis.
This is a process where glucose is produced. It is synthesized from nonglucose source.
Gluconeogenesis
What is the product of aspartate when combined with a-ketoglutarate?
Oxaloacetate and Glutamate
This is a carrier of Nitrogen, particularly Ammonia.
Glutamate
This is a waste product of protein.
Ammonia
What is the process of the conversion of Urea?
The Glutamate will carry the Ammonia to the liver and in the liver the Ammonia will be converted into Urea.
The highest concentration of AST can be found in?
A. Cardiac tissue
B. Liver
C. Skeletal muscle
The smaller amounts of concentration of AST can be found in?
A. Kidney
B. Pancreas
C. RBCs
What are the types of AST Isoenzyme?
A. Mitochondrial Isoenzyme
B. Cytoplasmic Isoenzyme
What are the scientific diagnoses of AST?
A.Hepatocellular disorders
B. Skeletal muscle involvement
If it is a mild degree of liver tissue injury, what is predominant?
Cytoplasmic Isoenzyme
What happens if there is a severe tissue damage?
Release of mitochondrial Isoenzyme
Enumerate the AST elevations
A. Pulmonary embolism
B. Congestive Heart Failure
C. Viral hepatitis
D. Cirrhosis
E. Skeletal muscle disorders
Define pulmonary embolism
Their is a clot in the lungs. Therefore, it blocks the passage of the air which leads to Hypoxia.
What do you call the clotting in the deep vein of the leg?
Deep vein thrombosis
With pulmonary embolism, AST will be increased by how many times?
3x the Upper Limit of the Normal Value.
Describe briefly Hepatitis A, B, C,D and E.
A - fecal oral route (contaminated food)
B - Blood transfusion, sexually. (Newborns can be affected by infected mothers)
C - Same with B. However, blood transfusion is more prominent to drug users.
D - Co-infection with B because cannot replicate by itself
E - Same as A. Contributory factor is sanitation
This is the scarring of the liver.
Cirrhosis
What disease has an elevation up to 4x the upper limit of the normal value?
Cirrhosis
This is a group of conditions that weakens / degenerates muscles leading o muscle wasting.
Muscular dystrophies
With AMI or Heart Attack, what is always observed?
The pattern of elevation specifically the rise, peak and normalization.
After the onset of AMI, the measurement of elevation is done after how many hours?
6 - 8 hours
How many days does normalization take place?
4 -5 days.
This is the key link b/w TCA cycle and Glycolysis
Pyruvate
PYRUVATE:
It is the ________ to the formation of ________ wherein the pyruvate is transferred to the _____________ and it is converted into _________________.
Precursor; ATP; Mitochondria; Acetyl Co-enzyme A
Which is more live specific enzymes of the transferases, ALT or AST?
ALT
What is the diagnostic significance of ALT?
A. Evaluation of hepatic disorders (hepatocellular)
B. Progressive inflammatory liver conditions
This condition has a higher ALT elevation than AST
Progressive Inflammatory Liver Conditions
This is the AST:ALT ratio.
De Ritis Ratio
What are these when it comes to De Ritis Ration?
A. <1.0
B. >1.0 but <2.0
C. >2.0
A. Normal, even with viral hepatitis
B. Associated with Cirrhosis
C. Associated with alcoholic hepatitis and hepatocellular carcinoma
In acute hepatocellular injury, why is AST>ALT initially and after 24-48 hours the ALT is higher than the AST?
Because of the AST activity in hepatocytes and ALT has a longer half-life.
What is the formula for De Ritis Ratio?
AST RESULT / ALT RESULT
This method of measurement is the reaction of Transaminase couple to specific DH reactions.
Continuous-Monitoring method.
This Assay method is couple with enzymatic reaction with MDH. And, it monitors change in absorbance at 340nm.
Karmen Method
What is the indicator method of Karmen method?
Malate Dehydrogenase Enzyme
What is the optimal pH of Karmen Method?
7.3 - 7.8
What are the sources of errors of AST?
Hemolysis
AST activity in RBC is _________ higher than the serum.
15x
AST is stable in serum for ________ at 4’C.
3 - 4 days
What is the reference range of AST?
5 - 30 U/L
What is the indicator reaction of ALT?
LDH
What are the sources of errors of ALT?
ALT is unaffected by hemolysis because RBC activity in RBCs is only 7x higher than in normal serum.
What is the reference range of ALT?
6 -37 U/L
In colorimetric method, AST/ALT is couples with ____________.
2,4 - DNPH (Reitmann-Frankel)
In colorimetric method, _____________ of _____________ and pyruvate are more chromogenic.
Phenylhydrazones; Oxaloacetate
This method is still feasible and simple and limited BUT acceptable accuracy.
Colorimetric Method
