Double dioxygenation by mouse 8S-lipoxygenase: specific formation of a potent peroxisome proliferator-activated receptor alpha agonist.
Mouse 8S-lipoxygenase (8-LOX) metabolizes arachidonic acid (AA) specifically to 8S-hydroperoxyeicosatetraenoic acid (8S-HPETE), which will be readily reduced under physiological circumstances to 8S-hydroxyeicosatetraenoic acid (8S-HETE), a natural agonist of peroxisome proliferator-activated receptor alpha (PPAR alpha). Here, we investigated whether 8-LOX could further oxygenate AA and whether the products could activate PPARs. The purified recombinant 8-LOX converted AA exclusively to 8S-HPETE and then to (8S,15S)-dihydroperoxy-5Z,9E,11Z,13E-eicosatetraenoic acid (8S,15S-diHPETE). The kcat/Km values for 8S-HPETE and AA were 3.3x10(3) and 2.7x10(4) M(-1) s(-1), respectively. 8-LOX also dioxygenated 8S-HETE and 15S-H(P)ETE specifically to the corresponding 8S,15S-disubstituted derivatives. By contrast, 15-LOX-2, a human homologue of 8-LOX, produced 8S,15S-diH(P)ETE from 8S-H(P)ETE but not from AA nor 15S-H(P)ETE. 8S,15S-diHETE activated PPAR alpha more strongly than 8S-HETE did. The present results suggest that 8S,15S-diH(P)ETE as well as 8S-H(P)ETE would contribute to the physiological function of 8-LOX and also that 8-LOX can function as a potential 15-LOX.
Jisaka
Mitsuo
M
Department of Life Science and Biotechnology, Shimane University, Matsue, Shimane 690-8504, Japan. jisaka@life.shimane-u.ac.jp
Iwanaga
Chitose
C
Takahashi
Nobuyuki
N
Goto
Tsuyoshi
T
Kawada
Teruo
T
Yamamoto
Tatsuyuki
T
Ikeda
Izumi
I
Nishimura
Kohji
K
Nagaya
Tsutomu
T
Fushiki
Tohru
T
Yokota
Kazushige
K
D000818:Animals; D001093:Arachidonate 15-Lipoxygenase / Q000235:genetics; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000096:biosynthesis*; D007700:Kinetics; D008084:Lipoxygenase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D051379:Mice; D010100:Oxygen / Q000378:metabolism*; D047493:PPAR alpha / Q000819:agonists* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D013379:Substrate Specificity
D006893:Hydroxyeicosatetraenoic Acids; D047493:PPAR alpha; D011994:Recombinant Proteins; D008084:Lipoxygenase; C458528:ALOX15B protein, human; D001093:Arachidonate 15-Lipoxygenase; D010100:Oxygen