4. Localization of enzymes
• intracellular
• Lysosome
• Nucleous
• Cytosol
• Mithochondria
• Extracellular
• Are secreted and function out from the cell
• Mainly digestive enzymes (alfa amylase)
12. Tissue sources
• Kidney, brain, prostate, pancreas
and liver
Clinical significance
• Biliary tract obstruction
• Medications (warfarin,
phenobarbital and phenytoin)
• Alcohol consumption
• GGT activity is normal during
pregnancy and in patients with
bone disorders, conditions that
exhibit elevated ALP activity
13. Alkaline phosphatase
• ALP
• catalyze the hydrolysis of various phosphomonoesters at an alkaline
PH
• Require Mg++
• Tissue sources
• Bone, liver, intenstin, spleen,
• Placenta, kidney
15. 5’-nucleotidase
• A phosphatase that acts only on nucleoside 5’-phasphates, such as
AMP and adenylic acid, releasing inorganic phosphate.
• Mainly increase in hepatobiliary disease
17. Amylase
• AMS
• Catalyze hydrolysis of α, 1-4 glycosidic bonds in starch and glycogen to
produce glucose, maltose and intermediate chains called dextrins which
contain α, 1-6 branching linkages.
• Require Calcium
• Normally seen in urine
• Tissue sources
• Pancreas
• Salivary gland
• Clinical significance
• Acute pancreatitis
• Mumps
18. Lipase
• catalyzes the hydrolysis of triglycerides to produce glycerol and fatty
acids
• Tissue source
• Pancreas
• Clinical significance
• Acute pancreatitis
• lipase activity increases 5 to 8 hours after the onset of symptoms, peak at 24
hours and a return to normal after 8 to 14 days.
20. Creatine Kinase
• CK/ CPK
• catalyze the reversible phosphorylation of creatine to creatine
phosphate by ATP
• It is an enzyme found primarily in the heart and skeletal muscles
• Dimer with subunits B and M
21. Isoenzy
me
name
Compo
sition
Present in Elevated in
CK-1
Fast
moving
BB
Brain,prostate,GI
tract,lung,bladder,uteru
s,placenta
CNS diseases
CK-2
2% of
total
MB Myocardium/ Heart
Acute myocardial
infarction
CK-3
Slow
moving
MM
Skeletal muscle,
Myocardium
22. Clinical
significance
• AMI
• Muscular dystrophy
• Following MI, the CK-MB levels begin to rise
within 4 to 8 hours, peak at 12 to 24 hours and
return to normal levels within 48 to 72 hours
23. Lactate Dehydrogenase
• LD/ LDH
• catalyzes the interconversion of lactic to pyruvic acids. It is a
hydrogen-transfer enzyme that uses the coenzyme NAD+
• Tetramer (H and M)
25. Clinical significance
The highest levels of total LDH are seen in pernicious anemia and
hemolytic disorders
Liver disorders, such as viral hepatitis and cirrhosis show slight
elevations of two to three times ULN
In AMI, LDH levels begin to rise within 12 to 24 hours, reach peak levels
within 48 to 72 hours, and may remain elevated for 10 days
Skeletal muscle disorders and some leukemias contribute to increased
LDH levels
26.
27. Glycogen phosphorylase
• Glycogen phosphorylase uses inorganic HPO4
2+ to split glucose from
the polysaccharide chains of glycogen
• The glucose 1-phosphate so formed can be used for ATP synthesis in
muscle or converted to free glucose in the liver
• Requires pyridoxal phosphate as coenzyme
• Lack of glycogen phosphorylase result in Mc Ardle disease (glycogen
storage disease type 5) which causes muscle cramp and muscle
damage due to inadequate energy supply.
28. Enzymes as Analytic Reagents
• Measurement of substrates, drugs and enzyme activity
• Specific for substrate (advantage than chemical method)
• Direct measurement of the substrate in the complex mixture
• Methods for substrate measurements
• End point (the substrate is completely converted to product before it is
measured)
• Two-point Kinetic method (a change in substrate concentration produced
during a fixed-time interval is measured)
29.
30. Enzymes as therapeutic agents
• Transfusion of fresh blood or its active components in bleeding
disorders
• Oral administration of digestive enzymes in digestive diseases
• Administration of fibrinolytic enzymes (e.g. streptokinase)
• Cancer treatment
31.
32. Reference
• Tietz Fundamentals of Clinical Chemistry and Molecular Diagnostics
2015
• Clinical Chemistry Techniques Principles Correlations, Michael
L.Bishop and others, 2010
• Clinical chemistry, fundementals and laboratory techniques, Donna
L.Larson 2017