Abstract:  Lipoxygenase (LOX) from soybean was isolated and purified by Sephadex G-200 column chromatography. There were two LOX fraction obtained: LOX -1, LOX-2. The specific activities were increased to 5-fold and 9-fold, respectively. The optimum pH for LOX-1 was 7.0 whereas the LOX-2 was 9.0. The LOX-1 and Lox -2 had a same optimum temperature 25 ℃.LOX isozymes had a similar thermal stability. The isozymes were heat stable up to 40 ℃, but were rapidly inactivity by 30 min incubation at temperature higher than 50 ℃. The apparent Km values of LOX-1 and Lox-2 for LOX- LA (linoleic acid) were 8.2 m mol/L and 12.2m mol/L, respectively. The isozymes of LOX revealed different reaction with the metal ions likeCa²⁺、Na⁺、Cu²⁺and Fe³⁺.

Key words: soybean, lipoxygenase, isoenzyme, purification, property