Structure and kinetics of formation of catechol complexes of ferric soybean lipoxygenase-1.
Ferric soybean lipoxygenase forms stable complexes with 4-substituted catechols. The structure of the complex between the enzyme and 3,4-dihydroxybenzonitrile has been studied by resonance Raman, electron paramagnetic resonance, visible, and X-ray spectroscopies. It is a bidentate iron-catecholate complex with at least one water ligand. The kinetics of formation of complexes between lipoxygenase and 3,4-dihydroxybenzonitrile and 3,4-dihydroxyacetophenone have been studied by stopped-flow spectroscopy. The data are consistent with two kinetically distinct, reversible steps. The pH dependence of the first step suggests that the substrate for the reaction is the catechol monoanion. When these results are combined, plausible mechanisms for the complexation reaction are suggested.
Nelson
M J
MJ
E. I. du Pont de Nemours & Co., Wilmington, Delaware 19880-0328, USA.
Brennan
B A
BA
Chase
D B
DB
Cowling
R A
RA
Grove
G N
GN
Scarrow
R C
RC
D002396:Catechols / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008084:Lipoxygenase / Q000737:chemistry* / Q000378:metabolism; D008433:Mathematics; D009570:Nitriles / Q000737:chemistry / Q000378:metabolism; D013025:Glycine max / Q000201:enzymology*; D013053:Spectrophotometry; D013057:Spectrum Analysis; D013059:Spectrum Analysis, Raman; D014965:X-Rays
D002396:Catechols; D005290:Ferric Compounds; D009570:Nitriles; C053285:3,4-dihydroxybenzonitrile; D008084:Lipoxygenase