Title
Purification and characterization of two lipoxygenase isoenzymes from germinating barley
Author
Center for Phytotechnology, RUL-TNO
Doderer, A.
Kokkelink, I.
van der Veen, S.
Valk, B.E.
Schram, A.W.
Douma, A.C.
Publication year
1992
Abstract
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 μM 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 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. Chemicals/CAS: Amino Acids; Isoenzymes; Linoleic Acid, 2197-37-7; Linoleic Acids; Lipoxygenase, EC 1.13.11.12.
Subject
Barley
Germination
Isoenzyme
Linoleic acid hydroperoxide
Lipoxygenase
Purification
isoenzyme
lipoxygenase
amino acid sequence
article
barley
embryo
enzyme purification
germination
isoelectric point
molecular weight
nonhuman
ph
priority journal
Amino Acid Sequence
Amino Acids
Hordeum
Hydrogen-Ion Concentration
Isoenzymes
Kinetics
Linoleic Acid
Linoleic Acids
Lipoxygenase
Molecular Sequence Data
Seeds
Support, Non-U.S. Gov't
Hordeum vulgare subsp. vulgare
Pisum sativum
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DOI
https://doi.org/10.1016/0167-4838(92)90429-h
TNO identifier
231865
ISSN
0167-4838
Source
Biochimica et Biophysica Acta - Protein Structure and Molecular Enzymology, 1120 (1120), 97-104
Document type
article