Enzyme Kinetics MCAT Practice Question
A 45-year-old man with newly diagnosed type 2 diabetes mellitus undergoes testing for hexokinase activity as part of a research study examining glycolytic enzyme function. A researcher isolates hexokinase from a liver biopsy and measures its kinetic parameters using purified glucose as substrate. The enzyme preparation shows a Vmax of 480 Āµmol/min/mg protein and a Km of 0.12 mM. The hexokinase is known to be a tetramer with four identical subunits, each containing one active site. The enzyme concentration in the assay is 2.0 ĀµM. Which of the following best represents the turnover number (kcat) per individual subunit?
Answer choices
- A120 sā»Ā¹
- B60 sā»Ā¹Correct answer
- C30 sā»Ā¹
- D240 sā»Ā¹
- E480 sā»Ā¹
- F15 sā»Ā¹
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