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39 Cards in this Set
- Front
- Back
Enzymes |
-Biocatalysts -Macromolecules -Strictly confined inside the cell -Used as markers for cell / tissue injury or damage -Measured based on their activity
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Apoenzyme Holoenzyme Active site Allosteric site |
What are the enzyme structures? |
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Apoenzyme is the protein portion of an enzyme |
Define apoenzyme |
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Holoenzyme is the complete functional enzyme (apoenzyme + prosthetic group) |
Define holoenzyme |
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Active site is where the substrate attaches |
Define Active Site |
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Allosteric site is where regulatory molecule bind |
Define Allosteric Site |
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1. Emil Fisher's Lock and Key Theory 2. Kochland's Induced Fit Theory |
What are the two enzyme theories? |
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1. Change in substrate concentration 2. Change in coenzyme concentration 3. Change in product concentration |
What are the basis in measuring enzymatic activity? |
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1. Fixed-time 2. Continuous Monitoring |
What are the approaches in measuring enzyme activity? |
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Fixed-time |
- the reactants are combined and the reaction is allowed to proceed at a specified time - products formed are measured over a given amount of time - rate of reaction is directly proportional to enzyme concentration |
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Continuous Monitoring |
- Multiple measurements are made usually based on change in absorbance - measurements are made during the reaction either at given time intervals or continuous by a continuous reading spectrophotometer - preferred method because deviation in linearity is easily identifiable |
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- Rate of reaction is dependent on substrate concentration - This happens if the substrate concentration is less than the enzyme concentration |
Define the First Order Kinetics |
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- Rate of reaction is dependent on enzyme concentration - This happens if the enzyme concentration is less than the substrate concentration |
Define the Zero Order Kinetics |
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Alkaline and acidic |
Excessive ________ pH can affect and can denature enzymes. |
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Physiological blood pH |
Optimum working pH is the _________, however some perform with pH requirements. |
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37°C |
Optimum working temperature |
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40-50°C |
Temperature where rate of denaturation increases. |
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56°C |
Temperature where there is a complete denaturation. |
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-20°C |
Enzyme storage temperature |
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2°C to 8°C |
Substrate and coenzyme storage temperature |
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Directly |
ENZYME CONCENTRATION - Rate of reaction is ________ proportional with enzyme concentration in the presence of excess substrate. |
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Higher ; no longer increase |
SUBSTRATE CONCENTRATION - The higher the substrate concentration, the ______ the rate of reaction, however when all enzymes are bound with a substrate, the rate will ________. |
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Substances that enhance enzyme function |
Define Cofactors |
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1. Coenzymes - organic - NAD/NADH, pyridoxal phosphate 2. Activators - inorganic - electrolytes |
What are the 2 cofactors? |
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Substances that decrease enzyme reaction |
Define inhibitors |
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1. Competitive inhibitor 2. Noncompetitive inhibitor 3. Uncompetitive inhibitor |
What are the 3 types of inhibitors? |
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The inhibitor that competes with the substrate for the same binding site |
Define competitive inhibitor |
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The inhibitor that binds the enzyme on sites other than the active site. |
Define Noncompetitive inhibitor |
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The inhibitor that attaches the enzyme - substrate complex |
Define Uncompetitive Inhibitor |
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1. Substrate addition - reverses competitive inhibition - no effect to Noncompetitive inhibition - intensifies Uncompetitive Inhibition 2. Sample dilution - can reverse all type of inhibitions |
What are the remedies for inhibition? |
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- Different enzyme forms that maintains the same catalytic function throughout the body - May be differentiated from each other based on certain properties such as electrophoretic mobility, solubility, or resistance to inactivation. |
Define Isoenzymes |
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1. Oxidoreductases 2. Transferases 3. Hydrolases 4. Lyases 5. Isomerases 6. Ligases |
What are the different enzyme classifications? |
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Lactate dehydrogenase |
What is considered as the least specific enzyme? |
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Pernicious/megaloblastic anemia |
Highest elevation of LD is often seen in _________. |
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LD6 |
- alcohol dehydrogenase - present in arteriosclerotic cardiovascular failure - seen together with LD5 increase |
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LD - Flipped Pattern |
- LD1>LD2 - Hemolytic anemia and myocardial infarction |
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Duchenne's muscular dystrophy |
Highest elevation or CK is seen in _________. |
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Adenylate kinase |
In CK, hemolysis must be avoided due to the presence of _________ inside RBCs which mimics CK activity. |
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Acute viral hepatitis |
Highest elevation of Alanine aminotransferase is seen in _______. |