11. Phospholipase A2 cleaves the SN-2 acyl chain, releasing arachidonic acid . 12. It is synthesized from arachidonic acid in a reaction catalyzed by a cyclooxygenase enzyme. 13. This role cannot be met by any ?-3 fatty acids or by arachidonic acid . 14. The arachidonic acid cascade proceeds somewhat differently in the brain. 15. The enzyme possesses two catalytic activities as illustrated by its metabolism of arachidonic acid . 16. The cysteinyl leukotrienes, potent biological compounds derived from arachidonic acid . 17. The toxin-induced contraction was related to generation of thromboxane A 2 from arachidonic acid . 18. It has the ability to synthesize the polyunsaturated fatty acids eicosapentaenoic acid and arachidonic acid . 19. PGI 2 is derived from the ?-6 arachidonic acid . 20. This is not consistent with the results of the isotope experiments of arachidonic acid oxygenation.