scholarly journals A predicted transmembrane region in plant diacylglycerol acyltransferase 2 regulates specificity toward very-long-chain acyl-CoAs

2020 ◽  
Vol 295 (45) ◽  
pp. 15398-15406
Author(s):  
Simon Jeppson ◽  
Helena Mattisson ◽  
Kamil Demski ◽  
Ida Lager

Triacylglycerols are the main constituent of seed oil. The specific fatty acid composition of this oil is strongly impacted by the substrate specificities of acyltransferases involved in lipid synthesis, such as the integral membrane enzyme diacylglycerol acyltransferase (DGAT). Two forms of DGAT, DGAT1 and DGAT2, are thought to contribute to the formation of seed oil, and previous characterizations of various DGAT2 enzymes indicate that these often are associated with the incorporation of unusual fatty acids. However, the basis of DGAT2's acyl-donor specificity is not known because of the inherent challenges of predicting structural features of integral membrane enzymes. The recent characterization of DGAT2 enzymes from Brassica napus reveals that DGAT2 enzymes with similar amino acid sequences exhibit starkly contrasting acyl-donor specificities. Here we have designed and biochemically tested a range of chimeric enzymes, substituting parts of these B. napus DGAT2 enzymes with each other, allowing us to pinpoint a region that dramatically affects the specificity toward 22:1-CoA. It may thus be possible to redesign the acyl-donor specificity of DGAT2 enzymes, potentially altering the fatty acid composition of seed oil. Further, the characterization of a DGAT2 chimera between Arabidopsis and B. napus demonstrates that the specificity regulated by this region is transferrable across species. The identified region contains two predicted transmembrane helices that appear to reoccur in a wide range of plant DGAT2 orthologues, suggesting that it is a general feature of plant DGAT2 enzymes.

2015 ◽  
Vol 140 (4) ◽  
pp. 362-372 ◽  
Author(s):  
Joyce W. Ngure ◽  
Chunyan Cheng ◽  
Shuqiong Yang ◽  
Qunfeng Lou ◽  
Ji Li ◽  
...  

Cucumber (Cucumis sativus) seed oil has the potential for use as an edible oil and as a pharmaceutical, cosmetic, insecticidal, and industrial product. In this study, we investigated, for the first time, the effect of cultivar and season on seed number, oil content, and fatty acid profiles as well as their proportions in different cucumber cultivars. We examined the effects of spring and autumn seasons on seed oil content and fatty acid composition in 46 cucumber cultivars and one wild species of cucumber (C. anguria) grown in greenhouse experiments in 2013 and 2014. Seed oil was determined using the Soxhlet method and fatty acids using the gas chromatography-mass spectrometry method. Seed oil content in the cucumber seeds ranged from 41.07% in ‘Hazerd’ to 29.24% in ‘Lubao’ while C. anguria had 23.3%. Fatty acids detected were linoleic (C18:2), palmitic (C16:0), oleic (C18:1), stearic (C18:0), linolenic (C18:3), behenic (C22:0), arachidic C20:0), lignoceric (C24:0), eicosenoic (C20:1), palmitoleic (C16:1), and myristic (C14:0), among other unidentified fatty acids. The results showed significant effects of cultivar genotype, growing season, and interactions on the variables examined. The content of seed oil and fatty acids differed significantly among the cultivar genotypes. Spring-grown cucumbers had higher quantities of oil than the autumn-grown cucumbers. The content of fatty acids (mainly palmitic, palmitoleic, stearic, oleic, eicosenoic, and lignoceric) also was higher in spring. In autumn there were more seeds, and higher linoleic, linolenic, and other unspecified fatty acids. The higher the oleic acid content the lower was the linoleic acid indicating a strong negative relationship in these two fatty acids. The higher the seed oil content the higher was linoleic and oleic indicating a positive relationship between the seed oil and the two fatty acids. Results of this study provide important information applicable in improving management and production of cucumber seed oil especially considering its versatility in uses. Furthermore, the wide range of fatty acids found in the studied cucumber cultivars could be used in the production of novel industrial oils through genetic engineering.


Author(s):  
Beibei Zhao ◽  
Haodi Gong ◽  
Hua Li ◽  
Yan Zhang ◽  
Tao Lan ◽  
...  

AbstractThis work focused on physicochemical property assaying, fatty acid composition, triacylglycerol profiles, and sterols and squalene composition of the Chinese grape seed oil. Three different methods were used to extract oil from Chinese grape seeds, solvent extraction, cold press and hot press methods. Three oils all possess very low acid value and peroxide value, suggesting their good quality as edible oil. Fatty acid composition results indicated that the total content of unsaturated fatty acids was 89.14 %, within which the majority fatty acid was linoleic acid with content of 64.11 %. Characterization of triacylglycerol profiles was achieved by a two-dimensional HPLC coupling of nonaqueous reverse-phase and silver ion HPLC with atmospheric pressure chemical ionization mass spectrometry method. There was a total of 30 TAGs including 23 regioisomers that have been determined. Unsaponifiable matters composition results revealed that the total sterols content and the squalene content were 278.49 mg/100 g and 17.81 mg/100 g, respectively.


OCL ◽  
2019 ◽  
Vol 26 ◽  
pp. 32 ◽  
Author(s):  
Zhana Petkova ◽  
Ginka Antova

Current paper reveals the impact of thermal treatment on the quality of two seed oils – pumpkin and melon compared to the quality of the most used oil – sunflower oil. Conventional and microwave heating were used for processing the oils. The duration of the thermal treatment was 9, 12 and 18 min for the conventional heating. The microwave heating was performed with two microwave powers of the equipment (600 W and 900 W) for 3, 6, 9 and 12 min. At every stage of the thermal processing were determined acid and peroxide value, the absorbance of the oils at 232 and 268 nm, tocopherol and fatty acid composition. It was observed that the degree of oxidation of the examined oils during microwave and conventional heating increased with the duration of the thermal process and the power of the microwaves. Also, the two methods of heating had a little impact on the processes leading to the formation of free fatty acids. Total tocopherols of the melon seed oil were more stable to thermal treatment. The amount of linoleic acid decreased in the pumpkin and sunflower oils during microwave treatment, while that of oleic and palmitic acid relatively increased. The biggest change in the fatty acid composition of both oils was found during microwave heating at 900W. The changes in fatty acid composition of thermally treated melon seed oil were insignificant. Overall, melon seed oil was observed to be more thermally stable than pumpkin and sunflower oils.


2021 ◽  
pp. 1-11
Author(s):  
Mohammad Agha Mohammad Reza ◽  
Farzad Paknejad ◽  
Amir Hossein Shirani Rad ◽  
Mohammad Reza Ardakani ◽  
Ali Kashani

1996 ◽  
Vol 31 (4) ◽  
pp. 518-518
Author(s):  
A. I. Rezvukin ◽  
I. Yu Berezovikova ◽  
I. Ya Shalaurova ◽  
Yu. P. Nikitin

2020 ◽  
Vol 104 (5) ◽  
pp. 1410-1422
Author(s):  
Shan Tang ◽  
Dong‐Xu Liu ◽  
Shaoping Lu ◽  
Liangqian Yu ◽  
Yuqing Li ◽  
...  

Author(s):  
Syamsul RAHMAN ◽  
Salengke Salengke ◽  
Abu Bakar TAWALI ◽  
Meta MAHENDRADATTA

Palado (Aglaia sp) is a plant that grows wild in the forest around Mamuju regency of West Sulawesi, Indonesia. This plant is locally known as palado. Palado seeds (Aglaia sp) can be used as a source of vegetable oil because it contains approximately 14.75 % oil, and it has the potential to be used as food ingredients or as raw material for oil production. The purpose of this study was to determine the chemical properties and the composition of fatty acids contained in palado seed oil (Aglaia sp). The employed method involved the use of palado fruit that had been processed to be palado seed and undergoing flouring process. Palado flour was produced by the extraction process by using chloroform solvent with the soxhlet method. The characteristics of the chemical properties in the oil produced were analyzed by using a standard method, including iodine, saponification, and acid values. The analysis of fatty acid composition was conducted by using gas chromatography. The results showed that palado oil extracted with hexane had an iodine value of 15.38 mg/g, saponification value of 190.01 mg KOH/g, and acids value of 1.961 mg KOH/g. The fatty acid composition of the palado seed oil consisted of saturated fatty acids (41.601 %), which included palmitic acid (41.062 %), myristic acid (0.539 %), and unsaturated fatty acids (45.949 %), which included mono-unsaturated fatty acids (MUFA) such as (22.929 %), oleic acid and poly-unsaturated fatty acids (PUFA), which was linoleic acid (23.020 %).


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