Enzymology Flashcards
What does enzyme deficiency lead to?
Abnormal protein, reduced amount of protein, defective transport of enzyme to mitochondria
How can you detect cellular injury using enzymes?
Cellular injuries can lead to an increased level of specific enzymes in the serum.
Troponin
Non serum proteins that can be used to test if someone had a MI
Creatine Kinase
CK catalyzes a reversible reaction forming wither ATP from creatine phosphate (at low ATP levels) or forming creatine phosphate (CrP) at high ATP levels.
Creatine Phosphate
High energy molecule that can be formed from ATP and creatine kinase from the creatine molecule
Creatine Kinase
Found in the cytoplasm and mitochondria.
Cytosolic CK is the injury marker.
What are the two subunits for CK? What are the 3 CK isozymes?
The subunits are M and B. You can have
: CK-BB (CK-1), CK-MB (CK-2) or CK-MM (CK-3)
CK-BB
CK-1. Mainly found in the brain and intestinal smooth muscle.
CK-MM
CK-3. 98% of total CK in the skeletal muscle. You see an elevated CK-MM in the serum when there is damage to the skeletal muscle.
CK-MB
CK-2. makes up about 30% of the heart (rest is CK-3).
What is the serum marker of rhabdomylosis?
CK-MM (CK3)
What is the serum marker for muscular dystrophy?
CK-MM
What is the charge of CK isozymes?
Negative, migrate towards the anode.
Within the first 18 hours after a heart attack, what isozyme would you test for in the blood?
CK-MB
LDH Isozymes
Have the subunits H and M. Are good markers for M, skeletal muscle damage, and hepatitis.
When does LDH levels peak after a MI?
48 hours after an MI, can last in blood for about 5 days.
What LDH isozymes would you normally find in the heart?
LDH-1 (a lot) and LDH-2 (little)
What LDH isozymes would you normally find in RBSs?
LDH-1 and LDH-2 (lots)
What LDH isozymes would you find in some muscles?
LDH-3 and LDH5
What LDH isozymes would you find in skeletal muscle and the liver?
LDH-5
What is the “flip” of LDH pattern after a MI?
The normal low LDH1/LDH2 levels are replaced by a high level as the heart’s LDH isozymes are released into the blood
What are the markers for troponin for heart injury?
cTnI and cTnT
Elisa Test
tests for early MI markers in the serum. Tests for sharp CK-MB peak, cTnI and cTnT, and myoglobin.
When testing for liver integrity, what are your markers?
Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) which leak out of liver cells due to damage. Not specific.
