1. Enzyme Clinical Application
Biochemistry Department
Level 1
Lecture No :4
Date : / 1 / 2015
Enzyme Clinical Application
Dr. Marwa Matboly
Armed Forces College Of Medicine Biochemistry Department

3. Enzymes
O - C
Hi, Everybody! 。

4. Intended learning outcomes(ILO)
List some examples of drugs acting by competitive enzyme inhibition and others acting as irreversible enzyme inhibitors.
Summarize the various methods of enzyme regulation.
Describe the clinical importance of non functional plasma enzymes.
State the diagnostic importance of LDH, CPK, and alkaline phosphatase isoenzymes.
Explain the importance of enzymes as therapeutic agents.

5. Objectives Enzymes as Biological Catalysts The Properties of Enzymes
Enzyme classification
Enzyme kinetics
Factors affecting enzyme activity
Enzyme Inhibition
Regulation of enzyme activity.
Applications of Enzyme Action

6. Enzymes in clinical medicine
Diagnosis and prognosis of various diseases
Non functional plasma enzymes
Therapeutic agents

7. Enzymes in clinical medicine
1-plasma enzyme as diagnostic and prognostic yool

8. 1-Diagnosis of various diseases
Plasma enzymes
Isoenzymes

9. Lactate dehydrogenase
Diagnosis of diseases
Plasme enzymes
Functional
Non functional
Isoenzymes
Lactate dehydrogenase
Creatinine kinase

10. Functional
Plasma Enzymes
Non-Functional
Synthesis
by the liver
Intracellular enzymes Different body organs
(Released by normal cell turnover)
Function
Perform specific functions in blood
No physiological function in blood
Substrates In blood
Present
Absent
Plasma levels
Higher than those in tissues
Very low under normal conditions
They increase only in case of tissue damage; myocardial infarction ,hepatitis, cancer.
Examples
Enzymes of blood coagulation and fibrinolysis,
Lipoprotein lipase,
Lactate dehydrogenase
Creatinekinase
Transaminases
Alkaline phosphatase

11. Enzymes of diagnostic importance
Diagnostic use
Amylase and lipase
Pancreatitis
Acid phosphatase
Prostate cancer
Alk.phosphatase
Bone , liver diseases and hyperparathyroidism
Creatine kinase
Recent myocardial infarction
Lactate DH.
myocardial infarction liver diseases, Leukemia
Transaminases
myocardial infarction(SGOT) liver diseases(SGPT)

12. Indicator of cellular damage
Non functional plasma enzymes are present in higher concentration in cells compared to extracellualr fluid
Increased activity of non functional plasma enzymes in extracellular fluid
Indicator of cellular damage

13. Amount of non functional plasma enzyme released is proportionate to the degree of cellular damage

14. Non functional plasma enzymes
Unfortunately, there are few enzymes that are organ or tissue specific.
Examples:
Alcohol dehydrogenase in liver
Acid phosphatase in prostate
Pancreatic amylase and lipase

15. Isoenzymes
Study of isoenzyme increases the specificity of non functional plasma enzymes for various tissue
They are different molecular forms of the same enzyme synthesized by different tissues

16. Same Different Isoenzymes Catalyze the same reaction
Act on the same substrate
Use the same coenzymes
Same
Subunits
Vmax and Km
Physical properties
Electrophoretic mobility,
Immunogenic properties
Heat stability
Different

17. Examples of clinically important isoenzymes:
1-Lactate dehydrogenase
2-Creatinekinase.
3-Alkaline phosphatase

18. LDH1(HHHH) specific for HEART
Lactate dehydrogenase has Five isoenzymes present in blood
LDH1(HHHH) specific for HEART
LDH2(HHHM) " " RBCs
LDH3(HHMM) " " BRAIN
LDH4(HMMM) " " LIVER
LDH5(MMMM) " " MUSCLE

19. Electrophoresis of LDH
In myocardial infarction :Total serum LDH level increases due to elevation of LDH1 (cardiac) isozyme, electrophoresis is important to detect which fraction increased

20. Three isoforms are present -CK 1 (BB) (Brain) -CK2 (MB) (Heart)
Creatinekinase(CK)
Three isoforms are present
-CK 1 (BB) (Brain)
-CK2 (MB) (Heart)
-CK3 (MM) (Skeletal muscle)
In myocardial infarction there
is elevation of total CK with
marked elevation of CK2 (MB) after 4-8 hours
electrophoresis is important to detect which fraction increased

21. CK2 is used for early detection
LDH1 for follow up
In myocardial infarction, the cardiac isoenzymes of both CK&LDH are increased , CK2 rises within 4-8 hours after the onset of pain reaches peak within 24 hours. It returns to normal level after two-three days. LDH1 reaches its peak after hours returns to normal level after 48 hours

22. Alkaline phosphatase
ALP isoenzymes, present in blood, are derived from bone, liver, intestine, or placenta of pregnant woman
Electrophoretic separation of isoenzymes(different numbers of sialic acid residues) is performed to determine the organ affected.

23. Increased ALP Normal elevation Moderate increase Very high level
Pregnant women
Growing children
Adolescent
Moderate increase
Liver disease e.g. hepatitis ,obstructive jaundice
Very high level
Bone disease e.g. ricket, osteomalacia and cancer

24. Enzymes in clinical medicine
Therapeutic agents

25. Enzyme prepared from streptococcus
Some enzymes are used as Therapeutic agents
♥ Streptokinase:
Enzyme prepared from streptococcus
Used in clearing blood clots in myocardial infarction
Act by activating plasminogen to form plasmin.
Plasmin cleaves fibrin into several soluble components

26. Plasminogen
Sterptokinase
Plasmin
FDP
Fibrin

27. Asparginase is administrated decreasing asparagine level
♥ Asparaginase: enzyme used in therapy of adult leukemia ,.
Tumor cells have nutritional requirement for asparagine,
Asparginase is administrated decreasing asparagine level
Asparginase depresses the viability of tumor

28. Asparginase Aspargine is required as nutrition for tumor cells
Aspargine Aspartic acid
Aspargine is required as nutrition for tumor cells
Asparginase used in treatment of Leukaemia

29. Use of asparginase will decrease aspargine level so
inhibiting tumor growth (depress
the tumor vitality).
Leukemic cells have little or no ability to synthesize asparagine and must scavenge it from blood to synthesize their proteins