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Characterization and Immobilization of Marine Algal 11‐Lipoxygenase from Ulva fasciata
Author(s) -
Tsai Cheng Jung,
Li Wu Feng,
Pan Bonnie Sun
Publication year - 2008
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-008-1262-6
Subject(s) - lipoxygenase , chromatography , arachidonic acid , chemistry , biochemistry , linoleic acid , substrate (aquarium) , polyunsaturated fatty acid , enzyme , fatty acid , biology , ecology
The lipoxygenase (LOX) of the marine green alga Ulva fasciata was purified and immobilized in order to improve the stability and reusability. The algal LOX was partially purified by fractionation with 35–55% saturation of ammonium sulfate and MacroPrep high Q anion exchange chromatography. The LOX was purified ten times using linoleic acid (C 18:2 ) or arachidonic acid (C 20:4 ) as substrate, the Michaelis constant ( K m ) of LOX was 117.6, 31.3 μM, and maximum velocity ( V max ) was 12.8, 23.3 μmol hydroperoxy fatty acid/min‐mg protein, respectively. The algal LOX showed the highest activity towards C 18:4 followed by C 20:4 , C 18:2 and methyl ester of C 18:4 . LOX activity increased up to 10.5 times with increased concentration of Triton X‐100 in the extraction medium reaching an optimum at 0.05%. Calcium chloride, glutathione and phenylmethylsulphonyl fluoride were found effective protectants to LOX during purification. Hydroperoxyeicosatetraenoic acid (HpETE) formed from arachidonic acid catalyzed by this purified algal LOX was reduced and identified as 11‐hydroxy‐5,8,12,14‐eicosatetraenoic acid (11‐HETE) by NP‐HPLC and GC–MS. This algal 11‐LOX was immobilized in alginate beads. The stability was sevenfold greater than that of the unbound lipoxygenase at 4 °C in 0.05 M Tris–HCl buffer (pH 7.5). This is the first report on immobilization of a marine algal lipoxygenase with a view to its potential role in seafood flavor formation.