A 20-year-old male with no significant medical history comes to you with a urine positive for fructose. He does not have diabetes mellitus. Which enzyme is most likely to be deficient in this patient?
APyruvate kinase
BLactase
CFructokinase
DAldolase B
A 6-month-old boy is brought to the emergency department by his mother because of recurrent vomiting and yellowing of his eyes. The mother says that he has been eating poorly since she started weaning him off of breast milk 5 days ago. At this time, mashed vegetables and fruits were added to his diet. Examination shows scleral jaundice and dry mucous membranes. The tip of the liver is palpable 4 cm below the right costal margin. His serum glucose concentration is 47 mg/dL, serum alanine aminotransferase is 55 U/L, and serum aspartate aminotransferase is 66 U/L. Which of the following enzymes is most likely deficient?
AFructokinase
BGlucose-6-phosphatase
CGalactokinase
DGalactose-1 phosphate uridyltransferase
EAldolase B
A 59-year-old man comes to the physician because of bilateral blurry vision and difficulty driving at night that has been worsening progressively over the past 5 months. He has hypertension, type 2 diabetes mellitus, and hyperlipidemia. His hemoglobin A1c concentration is 8.9 mg/dL. A slit-lamp shows cloudy opacities of the lenses bilaterally. The patient's eye condition is most likely due to increased activity of which of the following enzymes?
AGalactokinase
BAldolase B
CSorbitol dehydrogenase
DAldose reductase
EGlucokinase
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