Linoleic , α-linolenic acid biosynthesis in plant leaves and a green alga

Harris, R. V.; James, A. T.

doi:10.1016/0005-2760(65)90062-7

Cited by 117 publications

(37 citation statements)

References 19 publications

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“…Most of the procedures have been documented in an earlier paper [3]. However, some additional techniques have been used.…”

Section: Methodsmentioning

confidence: 99%

“…The procedure is as follows : Cells are grown, harvested and pre-incubated in phosphate buffer as described by Harris and James [3]. I n experiments described here, only the "heavy" cells were used; these are sedimented a t 900xg for 10 min; the supernatant containing lighter cells is discarded.…”

Section: Preparation Of Chlorella Subcellular Enzymementioning

confidence: 99%

“…To the suspension is added 0.6 g insoluble polyvinylpyrrolidone (Polyclar AT, G. A. F. (Great Britain) Ltd., ManChester, purified by acid washing [13]) and the cells are disrupted ultrasonically as previously described [3]. The fraction designated "homogenate" is the supernatant obtained after sedimenting unbroken cells, debris and polyvinylpyrrolidone a t 1,500 x g for 10 min.…”

Section: Preparation Of Chlorella Subcellular Enzymementioning

confidence: 99%

“…Isolated chloroplasts from higher plants and algae readily synthesize saturated and monounsaturated fatty acids [i] and subcellular preparations from seeds synthesize linoleic acid [2], but so far only Chlorella vulgaris has yielded a chloroplast preparation capable of forming polyunsaturated fatty acids [3]. Work in this laboratory [3, 41, firmly established that Chlorella chloroplasts convert oleoyl-CoA into linoleate by an oxidative mechanism requiring NADPH and molecular oxygen as cofactors, but cannot activate the free fatty acid; the active form of the fatty acid is synthesized by the supernatant fraction of the cell.…”

mentioning

confidence: 99%

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The Mechanism of Formation of Polyunsaturated Fatty Acids by Photosynthetic Tissue

Gurr

Robinson

James

1969

European Journal of Biochemistry

142

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Labelled oleic acid, which is used as a substrate in studying the conversion of oleate into linoleate by Chlorella chloroplasts, is rapidly incorporated into the phospholipids. The phosphatidyl choline fraction accounts for almost all of the phospholipid label. Desaturation to linoleate lags behind the incorporation into lipids, but the newly synthesized linoleate remains esterified to phosphatidyl choline.[1-14C]Oleoy1-phosphatidyl choline, incubated with chloroplasts, is converted into [1-14C]-linoleoyl-phosphatidyl choline, but considerable difficulties arise in presenting the lipid to the enzyme in an acceptable form. Oleoyl-phosphatidyl choline formed in situ, however, does not present these difficulties and is desaturated a t a faster rate than the CoA derivative under conditions in which unesterified fatty acid cannot be LLactivated", and hence cannot be desatmated. We conclude that the precursor fatty acid can be transferred directly from the lipid to the desaturase enzyme and the product immediately accepted by a lipid to form a "desaturationacylation" cycle. Our data neither prove, nor exclude the possibility that the fatty acid is transformed while still attached to the lipid in ester linkage. esters are not the true substrates for the "desaturase". The work of Nagai and Bloch [6] with the stearoylacyl carrier protein desaturase of Euglena gracilis might suggest that the acyl carrier protein ester is the true substrate. However, the experiments of Nichols and James [7,8] have pointed to the possibility that phospholipids and glycolipids may have an important role to play in fatty acid transformations, while, more specifically, Harris et al. 141 have speculated about the possibility that phosphatidyl choline, which has a striklingly high specific activity with respect to newly biosynthesized linoleate in Chlorelh, may have special importance for the desaturation reaction.I n this paper, we shall report further studies which confirm that phosphatidyl choline is an important intermediate in the conversion of oleate into linoleate. MATERIALS AND METHODSMost of the procedures have been documented in an earlier paper [3]. However, some additional techniques have been used. Thin Layer ChromatographyTotal lipids were separated on thin layers (0.25 mm) of Silica Gel G with the solvent system:

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“…Most of the procedures have been documented in an earlier paper [3]. However, some additional techniques have been used.…”

Section: Methodsmentioning

confidence: 99%

Section: Preparation Of Chlorella Subcellular Enzymementioning

confidence: 99%

Section: Preparation Of Chlorella Subcellular Enzymementioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

The Mechanism of Formation of Polyunsaturated Fatty Acids by Photosynthetic Tissue

Gurr

Robinson

James

1969

European Journal of Biochemistry

142

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“…Up to now this enzyme has been evidenced only in four microsomal fractions: from developing seeds of safflower ( Carthamus tinctorius) [3], from Neurospora crassa [4], from potato tuber slices [1] and ChloreUa vulgaris [5]. Recently, Tremolieres and Mazliak [2] and, Slack and Roughan [6] have suggested a possible cooperation between the microsomes and the plastids of plant cells in the biosynthesis of a-linolenic acid, the first desaturation (oleic acid into linoleic acid) occurring in the microsomes and the second one (linoleic acid into linolenic acid) occurring in the plastids.…”

Section: Introductionmentioning

confidence: 99%

Sub‐cellular localization of the oleyl‐CoA desaturase activity in pea leaves

1976

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Non‐selective hydrolysis of tuna fish oil for producing free fatty acids containing docosahexaenoic acid

2013

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The nature of immobilised Candida antarctica lipase‐B (CAL‐B) catalysed hydrolysis of tuna fish oil was studied with parameters such as solvent and water concentration, temperature, speed of agitation and enzyme loading. Immobilised CAL‐B and support material immobead‐150 were characterised with BET surface area, particle size analyser and Fourier transform infrared spectroscopy (FT‐IR) to record their physiochemical properties. The maximum rate of reaction (Vmax) of 500 µmol of free fatty acids (FFAs) per mL reaction mixture per h and Michaelis−Menten constant (KM) of 2115 µmol FFAs/mL were found for Michaelis−Menten type kinetic model. Activation energy (E) of 26.1 KJ/mol was calculated for immobilised CAL‐B. The 55.9% conversion of triglycerides was observed after the third use of the immobilised CAL‐B. The activity retention of immobilised CAL‐B reduced to 33.5% after the fourth repeated use of the enzyme.

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Linoleic , α-linolenic acid biosynthesis in plant leaves and a green alga

Cited by 117 publications

References 19 publications

The Mechanism of Formation of Polyunsaturated Fatty Acids by Photosynthetic Tissue

The Mechanism of Formation of Polyunsaturated Fatty Acids by Photosynthetic Tissue

Sub‐cellular localization of the oleyl‐CoA desaturase activity in pea leaves

Non‐selective hydrolysis of tuna fish oil for producing free fatty acids containing docosahexaenoic acid

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