PURIFICATION AND CHARACTERIZATION OF 2 LIPOXYGENASE ISOENZYMES FROM GERMINATING BARLEY

被引:227
作者
DODERER, A [1 ]
KOKKELINK, I [1 ]
VANDERVEEN, S [1 ]
VALK, BE [1 ]
SCHRAM, AW [1 ]
DOUMA, AC [1 ]
机构
[1] HEINEKEN TECH BEHEER BV, ZOETERWOUDE, NETHERLANDS
关键词
BARLEY; LIPOXYGENASE; PURIFICATION; ISOENZYME; GERMINATION; LINOLEIC ACID HYDROPEROXIDE;
D O I
10.1016/0167-4838(92)90429-H
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Two lipoxygenase isoenzymes (linoleate:oxygen oxidoreductase, EC 1.13.11.12) present in the embryo of germinating barley seed have been purified to homogeneity and characterized. Both isoenzymes are monomeric proteins with a molecular mass of approx. 90 kDa and crossreact on Western blots with antibodies raised against pea lipoxygenase. They have an apparent K(m) of approx. 16-mu-M for linoleic acid. The isoenzymes differ in the product formed upon incubation with linoleic acid. One of the isoenzymes (lipoxygenase 1) solely forms the 9-HPOD as a product whereas the 13-HPOD is the major product formed by the other isoenzyme (lipoxygenase 2). Lipoxygenase 1 shows a pH-optimum of 6.5, is active in a broad pH range and has an isoelectric point of 5.2-5.3. Lipoxygenase 2 has the same pH optimum, but is active in a narrow pH range and has a significantly higher pI, namely 6.8-6.9. The occurrence of two isoenzymes was confirmed by peptide analysis of the proteins. Amino acid sequence data obtained from proteolytic fragments of lipoxygenase 1 show up to 50% identity with other plant lipoxygenases.
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页码:97 / 104
页数:8
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