A 50-year-old male presents with severe abdominal pain radiating to the back, nausea, and vomiting. Laboratory tests reveal elevated serum levels of amylase and lipase, suggesting acute pancreatitis. Which of the following best explains why serum amylase and lipase are used to diagnose this patient’s acute pancreatitis?

A 10-month-old boy is brought to the clinic for developmental delay, hepatosplenomegaly, and failure to thrive. Physical examination reveals abdominal distension and hypotonia. A genetic panel confirms Gaucher disease, an autosomal recessive lysosomal storage disorder. Which of the following enzyme replacement therapies would be most beneficial for this patient?

Patient Case: A 10-year-old male with hepatosplenomegaly and bone pain is diagnosed with Gaucher disease, a lysosomal storage disorder. He is started on enzyme replacement therapy with β-glucosidase to manage his symptoms. Question: Which of the following best describes the role of β-glucosidase in the treatment of this patient’s Gaucher disease?

A 45-year-old woman presents with jaundice, fatigue, and abdominal pain. Her past medical history is significant for alcohol use disorder. Laboratory tests reveal: Alanine aminotransferase (ALT): 250 U/L (Normal: <50 U/L) Aspartate aminotransferase (AST): 400 U/L (Normal: <40 U/L) Alkaline phosphatase (ALP): 120 U/L (Normal: 44–147 U/L) Total bilirubin: 3.5 mg/dL (Normal: <1.2 mg/dL) Which of the following is the most likely cause of this patient’s enzyme abnormalities?

A 58-year-old man with a history of hypertension and hyperlipidemia presents to the emergency department with severe chest pain radiating to the left arm for the past 4 hours. He appears diaphoretic and in distress. His electrocardiogram (ECG) shows ST-segment elevation in leads II, III, and aVF, concerning for an inferior myocardial infarction (MI). Which of the following is the most appropriate laboratory test for diagnosing this patient’s condition?

A 25-year-old male with a family history of metabolic disease undergoes testing for a suspected deficiency in a dehydrogenase enzyme involved in glucose metabolism. The laboratory uses a spectrophotometric assay showing reduced absorbance changes at 340 nm, suggesting low enzyme activity. How does the spectrophotometric assay detect the activity of Nicotinamide Adenine Dinucleotide (NAD⁺)-dependent dehydrogenases in this patient?

A 40-year-old female with a suspected autoimmune disorder is tested for specific autoantibodies. The laboratory uses an Enzyme-Linked Immunosorbent Assay (ELISA) with horseradish peroxidase as the reporter enzyme to confirm the presence of these antibodies in her serum. In the Enzyme-Linked Immunosorbent Assay (ELISA) used for this patient, what is the primary role of the reporter enzyme horseradish peroxidase?

A research team is developing an enzyme inhibitor drug for cancer therapy. They need to screen thousands of compounds for their ability to inhibit a key oncogenic enzyme. Which of the following techniques is most suitable for rapid, large-scale screening of enzyme inhibitors?

A 55-year-old male presents with chest pain and shortness of breath. An electrocardiogram suggests a myocardial infarction (heart attack). Blood tests reveal elevated levels of Lactate Dehydrogenase (LDH) isozymes, particularly LDH-1, which is predominant in cardiac tissue. Which of the following best explains why Lactate Dehydrogenase (LDH) isozymes are useful in diagnosing this patient’s condition?

A 60-year-old man presents with chest pain and shortness of breath. Electrocardiogram (ECG) reveals ST-segment elevation, and the patient is diagnosed with acute myocardial infarction (MI). The physician orders serum enzyme tests to confirm the diagnosis. Which of the following isozymes is most specific for detecting myocardial injury?