Inactivation of 15-lipoxygenases by acetylenic fatty acids.
The inactivation of soybean lipoxygenase-1 and of rabbit reticulocyte lipoxygenase by five selected acetylenic fatty acids was studied. In all cases the inactivation was time-consuming and depended on the concentration of the inactivator. The inactivation kinetics was measured and the data were fitted to a kinetic model based on the assumption of catalytic self-inactivation. The kinetic constants (Km-value and inactivation rate k2) calculated indicated that 7,10,13-eicosatrienoic acid was the most powerful inactivator for the soybean enzyme followed by 8,11,14-eicosatrienoic acid. The occurrence of an additional triple bond between C-4 and C-5 or between C-5 and C-6 strongly reduced the suicidal rate. With the reticulocyte enzyme, only small differences in the reactivities towards various acetylenic fatty acids have been observed.
Kühn
H
H
Institute of Biochemistry, Medical School (Charité), Humboldt University, Berlin, F.R.G.
Hayess
K
K
Holzhütter
H G
HG
Zabolotzski
D A
DA
Myagkova
G I
GI
Schewe
T
T
D015117:5,8,11,14-Eicosatetraynoic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D015126:8,11,14-Eicosatrienoic Acid / Q000494:pharmacology; D000818:Animals; D015118:Eicosapentaenoic Acid / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D007700:Kinetics; D008084:Lipoxygenase / Q000378:metabolism*; D016859:Lipoxygenase Inhibitors; D011817:Rabbits; D012156:Reticulocytes / Q000201:enzymology; D013025:Glycine max / Q000201:enzymology
D005231:Fatty Acids, Unsaturated; D016859:Lipoxygenase Inhibitors; D015117:5,8,11,14-Eicosatetraynoic Acid; C029510:4,7,10,13-eicosatetraynoic acid; D015118:Eicosapentaenoic Acid; D008084:Lipoxygenase; D015126:8,11,14-Eicosatrienoic Acid