enzymes, lipids, cardiac markers Flashcards
isoenzymes:
are different molecular forms of the same enzyme
There are different Isoenzymes for different tissues
Substrate inhibitors
An inhibitor that competes for an enzyme binding site
Uncompetitive inhibitors
After the enzyme binds the substrate, this inhibitor binds the E-S complex
Non-competitive inhibitor
Prevents substrate binding by altering the enzyme
Examples of Co-factors
Mg2+
Cu+
Mn2+
Oxidoreductases
LD (Lactate Dehydrogenase
Transferase
Creatinine Kinase
GGTP
AST
ALT
Hydrolase examples
Acid Phosphatase
Amylase
Alkaline Phosphatase
Lysases
Aldolase
factors affecting enzyme assays
Substrate Concentration
Temperature
pH
Clinical assays are designed to follow:
Zero Order Kinetics
Energy of Activation
The amount of energy required to convert reactants spontaneously to products
Inhibitors
A substrate that slows the rate of an enzymatic reaction
Holoenzyme
Complex of the apoenzyme, the inactive portion of the enzyme, and its cofactor(s)
Co-factors
Non-protein chemical compounds required for the enzyme’s biological activity to occur
The substrate conentration at which the velocity of the enzyme reaction is equal to 1/2 the max velocity
Km
Enzymes
Catalytic proteins present in all body cells
Which enzyme is most elevated in alcoholic cirrhosis?
GGT
Which 2 enzymes are most elevated in viral hepatitis?
AST
ALT
Which enzyme facilitates carbohydrate breakdown?
Amylase
You are unable to run alkaline phosphatase on your liver profile because the manufacturer has recalled the reagents. Which other enzyme(s) might you substitute which could give you information similar to alkaline phosphatase?
LAP
5”-nucleotidase
You receive a grossly hemolyzed specimen for LD assay on a patient with suspected liver disease. What is the best course of action?
Always obtain a new sample since elevation could lead to a false interpretation of liver disease in light of the suspected diagnosis.
Which enzyme/test pattern is diagnostic of MI?
A. Elevated CK with MB fraction present; LD elevated with a 1:2 flip; elevated AST, elevated troponin.
B. Elevated CK with MB fraction present; LD‑1 elevated; LD‑2 normal; normal AST, normal troponin.
C. Elevated CK with BB fraction; Normal LD, normal AST, normal troponin
D. Elevated CK with MM fraction, Elevated LD‑5, elevated AST, elevated troponin
A. Elevated CK with MB fraction present; LD elevated with a 1:2 flip; elevated AST, elevated troponin.