Year: 1986
Type: article
Abstract: Lipoxygenase-3, the major component of the enzyme in rice grain, was purified 2980-fold with a yield of 7% from embryos.The purified enzyme had a specific activity of 280 ^mol O2 formed/min per mg protein.This enzyme was inactivated by SH compounds, such as cysteine and glutathione.The inactivation was prevented by the addition of catalase or replacement of the air by N2 gas.These two treatments were also effective for the stable storage of the purified enzyme.The molecular weights measured by sodium dodecyl sulfate gel and gradient gel electrophoresis were 93,000 and 89,000, respectively, indicating that the enzyme is a single polypeptide chain.The purified enzymecontained 0.73 Fe atom per molecule.The absorption spectrum suggested that the enzymeis a non-hemeiron protein.Somesimilarities in amino-acid composition were observed between rice, soybean, and pea lipoxygenases.The purified enzyme specifically produced 9-dhydroperoxy-10, 12(is,Z)-octadecadienoic acid when linoleic acid was used as a substrate.Lipoxygenase (LOX, linoleate: oxygen oxidoreductase, EC 1.13.1 1.12) catalyzes the oxidation of methylene-interrupted unsaturated fatty acids and their esters such as linoleic and linolenic acids.LOX is widely distributed in higher plants.1}The enzyme was also found in rice bran2) and embryos,3) and three components (LOX-1, LOX-2 and LOX-3)
Institution: Kyoto University
Language: English
Subfield: Biochemistry
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W2034326100