2. Introduction
Enzymes are the Biocatalyst synthesized by living cells, which are
protein in nature, specific in their action
Enzymes are present virtually in all organs but slightly in different
forms and in different locations
They also act as reagent for various Bio-chemical estimation and
detections
Isoenzyme – multiple forms of an enzyme catalysing the same
reaction
3. Estimation of enzyme activities in biological fluids (particularly
plasma/serum) is of great clinical importance
The normal serum level of an enzyme indicates the balance between
its synthesis and release
Factors responsible for raises serum level
1. cellular damage
2. increased rate of cell turnover
3. proliferation of cells
4. increased synthesis of enzymes
4. Source: internet
Serum Enzymes are used as markers to detect the cellular damage
which ultimately help in diagnosis of diseases
Types: 1. Functional plasma enzymes
2. Non-functional plasma enzymes
i. Secretory enzymes : pepsin, amylase ,trypsin etc.
ii. Constitutive enzymes: LDH, ALP ,CPK
5. Clinical significance of Enzyme estimation
Useful in the diagnosis and early detection of diseases
Helpful in the detection of progress of diseases
Helpful in the detection of response to drugs in a diseases
Serum Enzyme activity is measured in: International units (IU/L)
8. Myocardial infraction (MI)
Besides chest pain ,changes in ECG, increase in biochemical markers
can also indicate the MI
Biochemical markers have excellent sensitivity for diagnosing
Acute myocardial infraction (AMI)
• Creatinine phosphokinase (CPK)
• Aspartate transaminase (AST)
• Lactate dehydrogenase (LDH)
• Cardiac troponins
• myoglobins
Source: internet
9. Creatinine phosphokinase: first enzyme to be
released into circulation with in 6-18 hours after
the infraction (CPK-MB)
Reaches a peak value in within 24-30 hours and
returns to normal level by second or third day
Aspartate transaminase (AST): Rises level in acute
MI after the CPK , Reaches to the peak in 48
hours and return normal with in 5 to 6 days
Lactate dehydrogenase: it rises generally from the
second day of infraction , Reaches peaks very fast
and returns to normal with in 15 days
Magnitude of rise is proportional to extent of
myocardial infraction
Source: U.Satyanarayana , textbook of biochemistry
10. Cardiac Troponins (CT): 3 components
Myoglobin: earlier marker for diagnosis of MI
Level rises with in 4 hours of infraction
False positive can occur in patients with renal failure
• Troponin T - increase with in 6 hours of MI and remain
elevated up to 7 days
• Troponin I - with in 4 hours of onset of MI
• Troponin C – calcium binding protein which helps in
activation of muscle contraction
11. Liver diseases
Enzyme level in serum is increased either by the damage to
hepatocytes and cholestasis
Amino transferases: sensitive indicator of liver cell injury and most
helpful in recognizing Hepatitis, jaundice, cirrhosis, hepatic necrosis
Cholestasis: Alkaline phosphatase
serum-glutamyl transpeptidase
1.Alanine transaminase
2.Aspartate transaminase
3.Lactate dehydrogenase
12. Cancer
Prostate cancer: Enzyme involved is Acid phosphatase
Found in great concentration in prostate gland and seminal fluid
Prostatic isoenzymes are more specific for prostatic cancer
Acid phosphatase levels drop by 50% with in one hour in RT , to
prevent preservatives should be added or stored in ice pack
High level : indicates tumor spread
Intermediate level: indicates prostatic infraction
Low levels: successful treatment of prostatic cancer
13. BONE DISEASES
Alkaline phosphatase: Rises in Rickets, hyperparathyroidism,
secondary malignancies of bone
Amylase: Acute pancreatitis, perforated intestinal ulcers, intestinal
obstruction
Lipase: level are rise in acute pancreatitis, perorated duodenal and
peptic ulcers
GI Tract