Podcast
Questions and Answers
What is the primary product formed when lactate is converted by lactate dehydrogenase?
What is the primary product formed when lactate is converted by lactate dehydrogenase?
- Pyruvate (correct)
- Hydrogen
- Lactate
- Ester
Which type of reaction does lactate dehydrogenase facilitate when lactate is converted to pyruvate?
Which type of reaction does lactate dehydrogenase facilitate when lactate is converted to pyruvate?
- Oxidation (correct)
- Reduction
- Hydrolysis
- Decarboxylation
What is the enzyme classification for lactate dehydrogenase?
What is the enzyme classification for lactate dehydrogenase?
- Dehydrogenase (correct)
- Lyase
- Transferase
- Hydrolase
What does the first digit in the Enzyme Commission Nomenclature represent?
What does the first digit in the Enzyme Commission Nomenclature represent?
Which of the following enzymes is specifically responsible for transferring an amino group?
Which of the following enzymes is specifically responsible for transferring an amino group?
What type of reaction does an isomerase catalyze?
What type of reaction does an isomerase catalyze?
Which of the following enzyme classifications is responsible for the removal of carboxyl groups?
Which of the following enzyme classifications is responsible for the removal of carboxyl groups?
When pyruvate is converted back into lactate, what kind of reaction occurs?
When pyruvate is converted back into lactate, what kind of reaction occurs?
What is the primary target of the viral infection in Hepatitis B?
What is the primary target of the viral infection in Hepatitis B?
Which liver enzyme is primarily requested for assessing hepatocellular disorders?
Which liver enzyme is primarily requested for assessing hepatocellular disorders?
Why is AST not considered a reliable marker for heart problems?
Why is AST not considered a reliable marker for heart problems?
In the context of liver diseases, what does ULN stand for?
In the context of liver diseases, what does ULN stand for?
Which of the following is NOT a typical cause of Hepatitis B?
Which of the following is NOT a typical cause of Hepatitis B?
What is the function of the enzyme ALT?
What is the function of the enzyme ALT?
What condition can lead to elevated levels of ALT and AST?
What condition can lead to elevated levels of ALT and AST?
Which enzyme is primarily found in cardiac tissues?
Which enzyme is primarily found in cardiac tissues?
Which organ is NOT a common source of alkaline phosphatase (ALP) isoenzyme?
Which organ is NOT a common source of alkaline phosphatase (ALP) isoenzyme?
What is the primary application of ALP testing in laboratory settings?
What is the primary application of ALP testing in laboratory settings?
What is the optimum pH range for alkaline phosphatase (ALP) activity?
What is the optimum pH range for alkaline phosphatase (ALP) activity?
Why is it important to differentiate ALP isoenzymes?
Why is it important to differentiate ALP isoenzymes?
Which of the following is NOT a commonly tested isoenzyme of ALP?
Which of the following is NOT a commonly tested isoenzyme of ALP?
Which cells are primarily responsible for the production of bone ALP?
Which cells are primarily responsible for the production of bone ALP?
What is a key reason for testing ALP despite its high levels?
What is a key reason for testing ALP despite its high levels?
How is intestinal ALP primarily bound in the body?
How is intestinal ALP primarily bound in the body?
What is the primary function of the enzymes produced by the pancreas?
What is the primary function of the enzymes produced by the pancreas?
Which enzyme is NOT produced by the pancreas?
Which enzyme is NOT produced by the pancreas?
What is indicated by a high level of amylase in urine?
What is indicated by a high level of amylase in urine?
When can a rise in amylase levels be observed after the onset of acute pancreatitis?
When can a rise in amylase levels be observed after the onset of acute pancreatitis?
Which isoenzyme of amylase is predominant during acute pancreatitis?
Which isoenzyme of amylase is predominant during acute pancreatitis?
What is the major distinction of amylase when filtered by the glomerulus?
What is the major distinction of amylase when filtered by the glomerulus?
At what time is amylase level expected to peak after the onset of pancreas inflammation?
At what time is amylase level expected to peak after the onset of pancreas inflammation?
Which location contributes to the initial digestion of starch?
Which location contributes to the initial digestion of starch?
What condition is commonly associated with cholestasis during pregnancy?
What condition is commonly associated with cholestasis during pregnancy?
Which event occurs when bile flow is obstructed?
Which event occurs when bile flow is obstructed?
What pathological condition can result from blocked bile flow?
What pathological condition can result from blocked bile flow?
What leads to damage of hepatocytes in obstructive conditions?
What leads to damage of hepatocytes in obstructive conditions?
What role does IgG play in the bile?
What role does IgG play in the bile?
In cases of bile duct blockage, which normal body process is disrupted?
In cases of bile duct blockage, which normal body process is disrupted?
Which liver condition is indicated by an alkaline phosphatase (ALP) level less than 3 times ULN?
Which liver condition is indicated by an alkaline phosphatase (ALP) level less than 3 times ULN?
What is a significant effect of cholestasis on bile flow during pregnancy?
What is a significant effect of cholestasis on bile flow during pregnancy?
Study Notes
Inflammation and Cyclooxygenase
- Inflammation is initiated by cyclooxygenase, an enzyme that produces prostaglandins.
- Lactate is the substrate converted to pyruvate by lactate dehydrogenase through oxidation (removal of hydrogen ion).
Enzyme Nomenclature
- Enzymes are typically named by their substrate + "-ase" (not universally applicable).
- Examples include:
- Lipid = lipase
- Ester = esterase
- Protein = protease
- The type of reaction is indicated in enzyme names:
- Oxidation = oxidase
- Reduction = reductase
- Hydrolysis = hydrolase
- Dehydrogenase = removes hydrogen atoms
- Decarboxylase = removes carboxyl groups
Enzyme Commission Nomenclature (E.C.)
- E.C. numbers classify enzymes based on:
- 1st digit: class
- 2nd digit: subclass
- 3rd & 4th: serial number
- Example: E.C. 2.6.1.1 corresponds to L-Aspartate 2-Oxaloglutarate aminotransferase, which transfers amino groups.
Isomerases and Transferases
- Isomerases rearrange functional groups within a molecule.
- Transferases facilitate the transfer of functional groups other than hydrogen between substrates.
Amylase Properties
- Molecular weight of amylase: 50,000 – 55,000.
- Readily filtered by glomerulus, not reabsorbed in tubules, allowing for urine detection.
- First amylase enzyme discovered was from urine sample, referred to as general amylase, not specific.
Diagnostic Significance of Amylase
- Elevated amylase indicates acute pancreatitis, peaking 24 hours post-onset.
- Hepatitis and cirrhosis lead to ALT and AST elevations, with chronic liver conditions presenting significantly high values (up to four times upper limit of normal).
Enzyme Classification: Alkaline Phosphatase (ALP)
- Systematic name: Orthophosphoric Monoester Phosphohydrolase (Alkaline).
- Optimum pH for activity: 9.0 - 10.0.
- Used to confirm hepatobiliary disorders including cholestasis, biliary obstruction, and viral hepatitis.
Specific Conditions Related to Enzyme Levels
- Biliary Tract Obstruction raises ALP levels 4-10 times the upper limit of normal (ULN) due to increased synthesis induced by cholestasis.
- Hepatocellular disorders typically show ALP elevations of less than three times ULN, while severe conditions may reach higher levels.
- Elevated estrogen in pregnant women can lead to cholestasis, affecting bile flow and increasing the risk of cholangitis.
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Description
This quiz covers key concepts related to biochemistry, focusing on enzymes such as lactate dehydrogenase and the processes of substrate conversion. You'll explore the roles of enzymes, including cyclooxygenase and the biochemical reactions they facilitate. Test your understanding of nomenclature and oxidation reactions.
