MK-886 (L 663536) is an inhibitor of leukotriene biosynthesis, inhibiting 5-lipoxygenase-activating protein (FLAP). It is also a moderately potent PPARα antagonist.

COX-1:8 μM, COX-2:58 μM

MK-886是一种抑制5-脂氧合酶激活蛋白(FLAP)的化合物，能强效抑制完整细胞内的白三烯生物合成，常用于确定5-脂氧合酶(EC 1.13.11.34)途径在细胞或动物模型中对炎症、过敏、癌症和心血管疾病的作用。MK-886对分离的COX-1的抑制作用（IC50=8 µM），可以阻断由COX-1衍生的产物12(S)-羟基-5-顺-8,10-反-十七碳三烯酸(12-HHT)和血栓素B2在人类洗涤血小板中对胶原蛋白以及外源性花生四烯酸的响应中的形成（IC50=13–15 µM）。分离的COX-2受到的影响较小（IC50=58 µM），在A549细胞中，MK-886（33 µM）未能抑制COX-2依赖的6-酮前列腺素（PG）F1α的形成。MK-886（10 µM）能抑制COX-1介导的血小板聚集反应，该反应由胶原蛋白或花生四烯酸诱导，而由凝血酶或U-46619（COX独立）诱导的聚集并不受影响[1]。

连续每日通过腹腔注射MK-886会增加从前额叶皮层获取的大脑样本中GluR1的磷酸化水平。相比之下，单次注射MK-886并不改变大脑皮质GluR1的磷酸化水平[2]。

Enzyme assay is conducted in buffer containing 25 mM Tris, pH 8.0, 1 mM DTT, 1 mM spermine, 50 mM KCl, 0.01% Nonidet P-40, and 1 mM MgCl2. PARP reaction contains 0.1 μCi [3H]NAD+ (200 000 DPM), 1.5 μM NAD+, 150 nM biotinylated NAD+, 1 μg/mL activated calf thymus, and 1?5 nM PARP-1. Autoreactions utilizing SPA bead-based detection are carried out in 50 μL volumes in white 96-well plates. Compounds (e.g., MK-4827) are prepared in 11-point serial dilution in 96-well plate, 5 μL/well in 5% DMSO/Water (10× concentrated). Reactions are initiated by adding first 35 μL of PARP-1 enzyme in buffer and incubating for 5 min at room temperature and then 10 μL of NAD+ and DNA substrate mixture. After 3 h at room temperature, these reactions are terminated by the addition of 50 μL of streptavidin-SPA beads (2.5 mg/mL in 200 mM EDTA, pH 8). After 5 min, they are counted using a TopCount microplate scintillation counter. IC50 data is determined from inhibition curves at various substrate concentrations[1].

IL-1β-stimulated A549 cells (5×106/ml) are pre-incubated with MK-886 (MK, 33 μM), indomethacin (Indo, 10 μM), celecoxib (Cele, 5 μM) or vehicle (DMSO) for 15 min prior to the addition of 30 μM arachidonic acid. After 15 min at 37 °C, the amount of released 6-keto PGF1α was assessed by ELISA as described in the Materials and methods section. (Only for Reference)