Enzymic characterization of epidermis-derived 12-lipoxygenase isoenzymes

2001 ◽  
Vol 355 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Malte SIEBERT ◽  
Peter KRIEG ◽  
Wolf D. LEHMANN ◽  
Friedrich MARKS ◽  
Gerhard FÜRSTENBERGER
Keyword(s):  
Arachidonic Acid ◽  
Catalytic Activity ◽  
Linoleic Acid ◽  
Methyl Ester ◽  
Docosahexaenoic Acid ◽  
Methyl Esters ◽  
Acid Methyl Ester ◽  
Dienoic Acid ◽  
Acidic Ph ◽  
Acid Methyl

Substrate selectivity and other enzymic characteristics of two epidermis-derived lipoxygenases (LOXs), the epidermis-type (e) (12S)-LOX and (12R)-LOX, were compared with those of the platelet-type (p) (12S)-LOX. In contrast with p(12S)-LOX, e(12S)-LOX and (12R)-LOX exhibited no or very low reactivity towards the customary substrates linoleic acid and arachidonic acid but metabolized the corresponding fatty acid methyl esters, which, in contrast, were not accepted as substrates by p(12S)-LOX. Other esters of arachidonic acid and linoleic acid, including propan-2-yl and cholesterol esters, 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphocholine, 1-palmitoyl-2-linoleyl-sn-glycero-3-phosphoethanolamine, and ceramide 1 carrying an ω-linoleic acid ester, were not metabolized by these three LOX isoenzymes. Among various polyunsaturated fatty acids the isomeric eicosatrienoic acids were found to be oxygenated by e(12S)-LOX but not by (12R)-LOX. 4,7,10,13,16,19-Docosahexaenoic acid as a substrate was restricted to p(12S)-LOX. Variations in the pH and the Ca2+ content of the incubation medium affected the catalytic potential only slightly. Whereas (12R)-LOX activity increased in the presence of Ca2+ and with an acidic pH, Ca2+ had no effect on p(12S)-LOX and e(12S)-LOX; an acidic pH decreased the catalytic activity of the latter two. However, the catalytic activity of the epidermis-type isoenzymes, but not of p(12S)-LOX, was found to be markedly increased in the presence of DMSO. Under these conditions, e(12S)-LOX and (12R)-LOX oxygenated 4,7,10,13,16,19-docosahexaenoic acid to 14-hydroxy-4,7,10,12,16,19-docosahexaenoic acid and 13-hydroxy-4,7,10,14,16,19-docosahexaenoic acid respectively. In addition, (9R)-hydroxyoctadeca-10,12-dienoic acid methyl ester was generated from linoleic acid methyl ester by (12R)-LOX. Independently of the substrate, the catalytic activity of e(12S)-LOX and (12R)-LOX was always at most 2% of that of p(12S)-LOX with arachidonic acid as substrate.

scholarly journals Influence of Oryzanols Concentrate on the Oxidation of Methyl Ester Linoleic Acid and Study of Their Oxidation Products

2019 ◽  
Vol 8 (4) ◽  
pp. 37
Author(s):  
Bruno Irigaray ◽  
Iván Jachmanián ◽  
María A. Grompone
Keyword(s):  
Linoleic Acid ◽  
Methyl Ester ◽  
Sunflower Oil ◽  
Rice Bran Oil ◽  
Methyl Esters ◽  
Acid Methyl Ester ◽  
Oxidation Products ◽  
Antioxidant Power ◽  
Linoleic Acid Methyl Ester ◽  
Acid Methyl

Oryzanols are frequently found in rice bran oil but almost completely removed in the neutralization step when the oil is chemically refined. In this way, oryzanols can be recovered from the soapstocks to generate a concentrate. Thereby, they could be used as antioxidants in lipids for specific purposes. In the present work the antioxidant power of oryzanols concentrate (33% purity) was studied together with pure oryzanols and butylhydroxytoulene (BHT). Methyl esters were prepared from regular sunflower oil without antioxidants to which the antioxidants before mentioned were added in an effective concentration of 3x10-3 M. The samples were oxidized in a heating block with oxygen flow and the hydroperoxides of linoleic acid methyl ester were analyzed. It was observed that all antioxidants were able to protect the sunflower oil methyl esters from oxidation with respect to methyl esters without antioxidants. Oryzanols presented a notoriously lower protection ability compared to BHT. However, the formation of the linoleic acid methyl ester hydroperoxides and their proportion, for the same oxidation stage, did not show differences between the antioxidants used. Therefore, the oxidation kinetics were similar between the different antioxidants studied.

scholarly journals Evaluation of 3-Methylbutanoic Acid Methyl Ester as a Factor Influencing Flavor Cleanness in Arabica Specialty Coffee

2021 ◽  
Vol 11 (12) ◽  
pp. 5413
Author(s):  
Keiko Iwasa ◽  
Harumichi Seta ◽  
Yoshihide Matsuo ◽  
Koichi Nakahara
Keyword(s):  
Methyl Ester ◽  
Methyl Esters ◽  
Acid Methyl Ester ◽  
Chemical Compounds ◽  
Gas Chromatography Mass Spectrometry ◽  
Arabica Coffee ◽  
Acid Methyl ◽  
Coffee Brew ◽  
Coffee Beans ◽  
Specialty Coffee

This paper reports on the chemical compounds in arabica coffee beans with a high Specialty Coffee Association (SCA) cupping score, especially those in specialty coffee beans. We investigated the relationship between the chemical compounds and cupping scores by considering 16 types of Coffea arabica (arabica coffee) beans from Guatemala (SCA cupping score of 76.5–89.0 points). Non-targeted gas chromatography-mass spectrometry-based chemometric profiling indicated that specialty beans with a high cupping score contained considerable amounts of methyl-esterified compounds (MECs), including 3-methylbutanoic acid methyl ester (3-MBM), and other fatty acid methyl esters. The effect of MECs on flavor quality was verified by spiking the coffee brew with 3-MBM, which was the top-ranked component, as obtained through a regression model associated with cupping scores. Notably, 3-MBM was responsible for the fresh-fruity aroma and cleanness of the coffee brew. Although cleanness is a significant factor for specialty beans, the identification of compounds that contribute to cleanness has not been reported in previous research. The chemometric profiling approach coupled with spiking test validation will improve the identification and characterization of 3-MBM commonly found in arabica specialty beans. Therefore, 3-MBM, either alone or together with MECs, can be used as a marker in coffee production.

scholarly journals Autoxidation of Conjugated Linoleic Acid Methyl Ester in the Presence of α-Tocopherol: The Hydroperoxide Pathway

Lipids ◽  
2008 ◽  
Vol 43 (7) ◽  
pp. 599-610 ◽  
Author(s):  
Taina I. Pajunen ◽  
Mikael P. Johansson ◽  
Tapio Hase ◽  
Anu Hopia
Keyword(s):  
Linoleic Acid ◽  
Methyl Ester ◽  
Conjugated Linoleic Acid ◽  
Acid Methyl Ester ◽  
Linoleic Acid Methyl Ester ◽  
Acid Methyl

Effect of Saturation and Unsaturation of Fatty Methyl Esters on Biodiesel NOx Emission Characteristics

2015 ◽  
Vol 787 ◽  
pp. 766-770 ◽  
Author(s):  
J. Thangaraja ◽  
S. Rajkumar
Keyword(s):  
Fatty Acid ◽  
Methyl Ester ◽  
Fatty Acid Methyl Ester ◽  
Fatty Acid Methyl Esters ◽  
Methyl Esters ◽  
Acid Methyl Ester ◽  
Degree Of Saturation ◽  
Oxides Of Nitrogen ◽  
Nox Formation ◽  
Acid Methyl

Biodiesel is a renewable fuel and an attractive alternative to replace fossil diesel without major engine modifications. However, the emissions of oxides of nitrogen (NOx) from biodiesel fuelled engines are reported to be higher compared to diesel engine. The characteristics of biodiesel are known to depend on their fatty acid methyl ester (FAME) contents which vary with the feedstock. Thus the contribution of saturation and unsaturation of pure components of fatty acid methyl esters on NOx formation warrants a systematic investigation. This paper attempts to relate the composition of biodiesel with NOx formation. For this purpose, the NO formation from pure fatty acid methyl esters are predicted using extended Zeldovich reaction scheme. Also, the experiments are conducted for measuring oxides of nitrogen from a compression ignition engine operated using neat palm and karanja methyl esters and their blends providing biodiesel combinations of varying degree of saturation for investigation. The measured NOx concentrations are compared with the corresponding predictions to affirm the influence of fatty acid methyl ester on engine NOx characteristics. The results clearly indicate that the change in degree of saturation influences the NOx formation and an increase in the degree of saturation of biodiesel decreases the engine NOx emission.

Fatty Acid Composition of Seeds of Satureja thymbra and S. cuneifolia

2003 ◽  
Vol 58 (7-8) ◽  
pp. 502-504 ◽  
Author(s):  
Ahmet C. Gören ◽  
Gökhan Bilsel ◽  
Mehmet Altun ◽  
Fatih Satıl
Keyword(s):  
Fatty Acid ◽  
Methyl Ester ◽  
Methyl Esters ◽  
Octadecenoic Acid ◽  
Acid Methyl Ester ◽  
Octadecatrienoic Acid ◽  
Octadecanoic Acid ◽  
Hexadecanoic Acid ◽  
Acid Methyl ◽  
Main Components

Abstract The chemical composition of fatty acid methyl esters (FAMEs) from seeds of S. thymbra and S. cuneifolia were analyzed by GC/MS. 7 FAMEs were identified from the seeds of S. thymbra mainly as 9-octadecenoic acid methyl ester (43.9%), hexadecanoic acid methyl ester (11.4%), 9,12,15-octadecatrienoic acid methyl ester (Z,Z,Z) (30.2%), and octadecanoic acid methyl ester (14.1%), while from the seed of S. cuneifolia 10 FAMEs were obtained with the main components, similar to S. thymbra. These were identified as 9-octadecenoic acid methyl ester (10.1%), hexadecanoic acid methyl ester (methyl palmitate, 34.6%), 9,12,15-octadecatrienoic acid methyl ester (Z,Z,Z) (6.3%) and octadecanoic acid methyl ester (1.8%).

Potential of electrospray ionization mass spectrometry (ESI-MS), using direct infusion, to quantify fatty acid methyl esters (FAMEs) in biodiesel

2017 ◽  
Vol 9 (26) ◽  
pp. 3949-3955
Author(s):  
Rodrigo V. P. Leal ◽  
Gabriel F. Sarmanho ◽  
Luiz H. Leal ◽  
Bruno C. Garrido ◽  
Lucas J. Carvalho ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acid ◽  
Methyl Ester ◽  
Fatty Acid Methyl Esters ◽  
Methyl Esters ◽  
Acid Methyl Ester ◽  
Ionization Mass ◽  
Direct Infusion ◽  
Esi Ms ◽  
Acid Methyl

Fatty acid methyl ester (FAME) intensities, by ESI-MS, used to their quantification in biodiesel.

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