Firefly luciferase is the enzyme that allows fireflies to illuminate their abdom

Question

Firefly luciferase is the enzyme that allows fireflies to illuminate their abdomens. Because this light generation is an ATP-requiring reaction, firefly luciferase can be used to test for the presence of ATP. In this way, luciferase can test for the presence of life. The coupled reactions are

luciferin+O2?oxyluciferin+light

ATP?AMP+PPi

If the overall ?G of the coupled reaction is -6.80kJ/mol , what is the equilibrium constant, K, of the first reactions at 7?C ? The ?G for the hydrolysis of ATP to AMP is ?31.6 kJ/mol.

K= ?

Explanation / Answer

Overall DeltaG = -6.80 kJ/mol

Delta G = 31.6 - 6.8 =24.8 KJ

T = 7 + 273.15 =280.15 K

Delta G = -RT * Ln (K)


24.8 * 10^3 J = -(8.314 J/moles*k)(280.15K) * Ln (K)

So (Delta G)/(-RT) = Ln (K)

Ln K = -10.64

Thus k = 2.393*10^-5

Related Questions

Navigate

• Browse (All)
• Browse F
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.