Cells isolated from the lungs of experimental mice via alveolar lavage are being studied for their responses to various lipid molecules.
Results indicate that addition of arachidonic acid leads to increased production of PGE2 but that LTA₄ is not detected. Which of the following enzymes is most likely defective explaining the observed results?

Question

Quizplus · Accepted Answer

The Answer is B
EXPLANATION: LTA₄ is an intermediate in the linear eicosanoid synthesis pathway. The linear pathway is initiated through the action of LOXs of which there are 3 forms: 5-LOX, 12-LOX, and 15-LOX. It is 5-LOX that gives rise to the leukotrienes. Therefore, loss of LTA₄ detection would most likley be due to loss of 5-LOX activity given that arachidonic acid was utilized effectively as a cyclic pathway (PGE₂) substrate.

Cells Isolated from the Lungs of Experimental Mice Via Alveolar