scholarly journals Purification and some properties of potato tuber lipoxygenase and detection of linoleic acid radical in the enzyme reaction.

1977 ◽  
Vol 41 (5) ◽  
pp. 827-832 ◽  
Author(s):  
Jiro SEKIYA ◽  
Hitoshi AOSHIMA ◽  
Tadahiko KAJIWARA ◽  
Tamotsu TOGO ◽  
Akikazu HATANAKA
Keyword(s):  
Linoleic Acid ◽  
Potato Tuber ◽  
Enzyme Reaction ◽  
Acid Radical

Purification and Some Properties of Potato Tuber Lipoxygenase and Detection of Linoleic Acid Radical in the Enzyme Reaction

1977 ◽  
Vol 41 (5) ◽  
pp. 827-832 ◽  
Author(s):  
Jiro Sekiya ◽  
Hitoshi Aoshima ◽  
Tadahiko Kajiwara ◽  
Tamotsu Togo ◽  
Akikazu Hatanaka
Keyword(s):  
Linoleic Acid ◽  
Potato Tuber ◽  
Enzyme Reaction ◽  
Acid Radical

scholarly journals Radical adducts of nitrosobenzene and 2-methyl-2-nitrosopropane with 12,13-epoxylinoleic acid radical, 12,13-epoxylinolenic acid radical and 14,15-epoxyarachidonic acid radical. Identification by h.p.l.c.-e.p.r. and liquid chromatography-thermospray-m.s

1991 ◽  
Vol 276 (2) ◽  
pp. 447-453 ◽  
Author(s):  
H Iwahashi ◽  
C E Parker ◽  
R P Mason ◽  
K B Tomer
Keyword(s):  
Liquid Chromatography ◽  
Linoleic Acid ◽  
Hyperfine Splitting ◽  
Spin Trapping ◽  
Soybean Lipoxygenase ◽  
Acid Radical ◽  
Radical Adduct ◽  
The Masses ◽  
Hydroperoxylinoleic Acid ◽  
Additional Hyperfine

Linoleic acid-derived radicals, which are formed in the reaction of linoleic acid with soybean lipoxygenase, were trapped with nitrosobenzene and the resulting radical adducts were analysed by h.p.l.c.-e.p.r. and liquid chromatography-thermospray-m.s. Three nitrosobenzene radical adducts (peaks I, II and III) were detected; these gave the following parent ion masses: 402 for peak I, 402 for peak II, and 386 for peak III. The masses of peaks I and II correspond to the linoleic acid radicals with one more oxygen atom [L(O).]. The radicals are probably carbon-centred, because the use of 17O2 did not result in an additional hyperfine splitting. Computer simulation of the peak I radical adduct e.p.r. spectrum also suggested that the radical is carbon-centred. The peak I radical was also detected in the reaction of 13-hydroperoxylinoleic acid with FeSO4. From the above results, peak I is probably the 12,13-epoxylinoleic acid radical. An h.p.l.c.-e.p.r. experiment using [9,10,12,13-2H4]linoleic acid suggested that the 12,13-epoxylinoleic acid radical is a C-9-centred radical. Peak II is possibly an isomer of peak I. Peak III, which was observed in the reaction mixture without soybean lipoxygenase, corresponds to a linoleic acid radical (L.). The 12,13-epoxylinoleic acid radical, 12,13-epoxylinolenic acid radical and 14,15-epoxyarachidonic acid radical were also detected in the reactions of linoleic acid, linolenic acid and arachidonic acid respectively, with soybean lipoxygenase using nitrosobenzene and 2-methyl-2-nitrosopropane as spin-trapping agents.

scholarly journals An anaerobic reaction between lipoxygenase, linoleic acid and its hydroperoxides

1971 ◽  
Vol 122 (3) ◽  
pp. 327-332 ◽  
Author(s):  
G. J. Garssen ◽  
J. F. G. Vliegenthart ◽  
J. Boldingh
Keyword(s):  
Linoleic Acid ◽  
Dienoic Acid ◽  
Structural Rearrangement ◽  
Soya Bean ◽  
Acid Radical ◽  
Hydrogen Radical ◽  
Anaerobic Reaction ◽  
Anaerobic System

In an anaerobic system soya-bean lipoxygenase together with linoleic acid induces a structural rearrangement of 13-hydroperoxyoctadeca-cis-9-trans-11-dienoic acid leading to the formation of 13-oxotrideca-cis(trans)-9-trans-11-dienoic acid and n-pentane as well as 13-oxo-octadeca-9,11-dienoic acid. It is proposed that the 13-peroxyoctadeca-cis-9-trans-11-dienoic acid radical formed through hydrogen radical abstraction by the linoleic acid radical is the key intermediate for these reactions.

Effect of Modification of Arginine Residues on the Activity of Soybean Lipoxygenase-1

1995 ◽  
Vol 50 (1-2) ◽  
pp. 37-44 ◽  
Author(s):  
Kenji Matsui ◽  
Hiroyuki Shinta ◽  
Tadahiko Kajiwara ◽  
Akikazu Hatanaka
Keyword(s):  
Linoleic Acid ◽  
Salt Concentration ◽  
Enzyme Reaction ◽  
Arginine Residue ◽  
Sodium Borate ◽  
Chemical Modifier ◽  
Soybean Lipoxygenase ◽  
Assay Condition ◽  
Product Specificity ◽  
Arginine Residues

Abstract Arginine residues of soybean lipoxygenase-1 was modified with an arginine-directed chemical modifier, 2,3-butanedione. Although inactivation was not visible if the enzyme reaction was monitored under the standard assay condition (83.3 μᴍ linoleic acid dispersed in 200 mᴍ sodium borate, pH 9.0), rapid inactivation was observed with 5 mᴍ sodium borate, pH 8.0. The inactivation was protected by the addition of a substrate, linoleic acid, in the modification mixture. Kinetic analyses indicated that one arginine residue accounted for the inactivation. Enzymological analyses showed that the modification narrowed the pH-activity profile of L-1 and made L-1 sensitive to salt concentration of the assay solution. Strong inactivation by modification was found at low salt concentration and low pH. This was not due to a physical change of the linoleic acid. On the other hand, product specificity of L-1 was not altered after modification. Taken together, the modified arginine residue(s) was thought to be not essential to the catalysis but have an important role in supporting an ideal electrostatic interaction within L-1 and/or between L-1 and a substrate even in sub-optimal reaction conditions.

Lead aspartate: a new en bloc stain for electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 34-35
Author(s):  
J.R. Walton
Keyword(s):  
Electron Microscopy ◽  
Calcium Ion ◽  
Enzyme Reaction ◽  
Lead Citrate ◽  
Reaction Products ◽  
En Bloc ◽  
Thin Sections ◽  
Lead Salts ◽  
Thin Sectioning ◽  
High Alkalinity

In electron microscopy, lead is the metal most widely used for enhancing specimen contrast. Lead citrate requires a pH of 12 to stain thin sections of epoxy-embedded material rapidly and intensively. However, this high alkalinity tends to leach out enzyme reaction products, making lead citrate unsuitable for many cytochemical studies. Substitution of the chelator aspartate for citrate allows staining to be carried out at pH 6 or 7 without apparent effect on cytochemical products. Moreover, due to the low, controlled level of free lead ions, contamination-free staining can be carried out en bloc, prior to dehydration and embedding. En bloc use of lead aspartate permits the grid-staining step to be bypassed, allowing samples to be examined immediately after thin-sectioning.Procedures. To prevent precipitation of lead salts, double- or glass-distilled H20 used in the stain and rinses should be boiled to drive off carbon dioxide and glassware should be carefully rinsed to remove any persisting traces of calcium ion.

Conjugated Linoleic Acid Causes a Marked Increase in Liver α-Tocopherol and Liver α-Tocopherol Transfer Protein in C57BL/6 J Mice

2010 ◽  
Vol 80 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Pei-Min Chao ◽  
Wan-Hsuan Chen ◽  
Chun-Huei Liao ◽  
Huey-Mei Shaw
Keyword(s):  
Antioxidant Enzymes ◽  
Linoleic Acid ◽  
Conjugated Linoleic Acid ◽  
Thiobarbituric Acid ◽  
Control Group ◽  
Thiobarbituric Acid Reactive Substances ◽  
Control Groups ◽  
Protein Levels ◽  
Transfer Protein ◽  
And Control

Conjugated linoleic acid (CLA) is a collective term for the positional and geometric isomers of a conjugated diene of linoleic acid (C18:2, n-6). The aims of the present study were to evaluate whether levels of hepatic α-tocopherol, α-tocopherol transfer protein (α-TTP), and antioxidant enzymes in mice were affected by a CLA-supplemented diet. C57BL/6 J mice were divided into the CLA and control groups, which were fed, respectively, a 5 % fat diet with or without 1 g/100 g of CLA (1:1 mixture of cis-9, trans-11 and trans-10, cis-12) for four weeks. α-Tocopherol levels in plasma and liver were significantly higher in the CLA group than in the control group. Liver α-TTP levels were also significantly increased in the CLA group, the α-TTP/β-actin ratio being 2.5-fold higher than that in control mice (p<0.01). Thiobarbituric acid-reactive substances were significantly decreased in the CLA group (p<0.01). There were no significant differences between the two groups in levels of three antioxidant enzymes (superoxide dismutase, glutathione peroxidase, and catalase). The accumulation of liver α-tocopherol seen with the CLA diet can be attributed to the antioxidant potential of CLA and the ability of α-TTP induction. The lack of changes in antioxidant enzyme protein levels and the reduced lipid peroxidation in the liver of CLA mice are due to α-tocopherol accumulation.

Immunolocalization of extensin and potato tuber lectin in carrot, tomato and potato

1996 ◽  
Vol 97 (4) ◽  
pp. 708-718 ◽  
Author(s):  
Shu-xia Li ◽  
Allan M. Showalter
Keyword(s):  
Potato Tuber
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