FYX-051: a novel and potent hybrid-type inhibitor of xanthine oxidoreductase.
4-[5-(Pyridin-4-yl)-1H-1,2,4-triazol-3-yl]pyridine-2-carbonitrile (FYX-051) is a potent inhibitor of bovine milk xanthine oxidoreductase (XOR). Steady-state kinetics study showed that it initially behaved as a competitive-type inhibitor with a K(i) value of 5.7 × 10(-9) M, then after a few minutes it formed a tight complex with XOR via a Mo-oxygen-carbon atom covalent linkage, as reported previously (Proc Natl Acad Sci USA 101:7931-7936, 2004). Thus, FYX-051 is a hybrid-type inhibitor exhibiting both structure- and mechanism-based inhibition. The FYX-051-XOR complex decomposed with a half-life of 20.4 h, but the enzyme activity did not fully recover. This was found to be caused by XOR-mediated conversion of FYX-051 to 4-[5-(2-hydroxypyridin-4-yl)-1H-1,2,4-triazol-3-yl]pyridine-2-carbonitrile (2-hydroxy-FYX-051), as well as formation of 6-hydroxy-4-[5-(2-hydroxypyridin-4-yl)-1H-1,2,4-triazol-3-yl]pyridine-2-carbonitrile (dihydroxy-FYX-051) and 4-[5-(2,6-dihydroxypyridin-4-yl)-1H-1,2,4-triazol-3-yl]-6-hydroxypyridine-2-carbonitrile (trihydroxy-FYX-051) during prolonged incubation for up to 72 h. A distinct charge-transfer band was observed concomitantly with the formation of the trihydroxy-FYX-051-XOR complex. Crystallographic analysis of the charge-transfer complex indicated that a Mo-nitrogen-carbon bond was formed between molybdenum of XOR and the nitrile group of trihydroxy-FYX-051. FYX-051 showed a potent and long-lasting hypouricemic effect in a rat model of potassium oxonate-induced hyperuricemia, and it seems to be a promising candidate for the clinical treatment of hyperuricemia.
Department of Biochemistry and Molecular Biology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan.
Koji
K
Matsumoto
Ken
K
Okamoto
Naoki
N
Ashizawa
Takeshi
T
Nishino
D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D002417:Cattle; D018360:Crystallography, X-Ray; D008297:Male; D009570:Nitriles / Q000737:chemistry / Q000494:pharmacology*; D011725:Pyridines / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013329:Structure-Activity Relationship; D014968:Xanthine Dehydrogenase / Q000037:antagonists & inhibitors* / Q000302:isolation & purification / Q000378:metabolism*
D009570:Nitriles; D011725:Pyridines; C504882:FYX-051; D014968:Xanthine Dehydrogenase