Origin of Characteristic Properties of Natural Rubber—Synergistic Effect of Fatty Acids on Crystallization of cis-1,4-Polyisoprene: II, Mixed and Esterified Fatty Acids in Natural Rubber

1996 ◽  
Vol 69 (4) ◽  
pp. 608-614 ◽  
Author(s):  
Naoyuki Nishiyama ◽  
Seiichi Kawahara ◽  
Takashi Kakubo ◽  
Eng Aik Hwee ◽  
Yasuyuki Tanaka
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Natural Rubber ◽  
Free Fatty Acids ◽  
Crystallization Rate ◽  
Chain Fatty Acid ◽  
Long Chain Fatty Acid ◽  
Esterified Fatty Acids ◽  
Deproteinized Natural Rubber ◽  
Long Chain

Abstract Crystallization behavior of deproteinized natural rubber at −25°C was investigated by dilatometry in connection with the effect of long-chain fatty acid groups, esterified to the rubber chain, as well as free fatty acids and their esters. The overall crystallization rate decreased after removal of the acetone-extractable free fatty acids and their esters, while it increased significantly when the fatty acid groups esterified to natural rubber molecule were removed by transesterification with sodium methoxide. Both the acetone-extracted and transesterified rubbers showed a significant increase in the overall crystallization rate after the addition of 1 wt % stearic acid. The crystallization of acetone-extracted rubber was accelerated by the addition of 1 wt % methyl linoleate, a plasticizer of natural rubber, whereas it was suppressed in the case of transesterified rubber in which the esterified fatty acid groups were removed completely. The fatty acid groups esterified to natural rubber molecule gave rise to the accelerated crystallization of the rubber in conjunction with free fatty acids and their esters.

scholarly journals Biochemical effects of the hypoglycaemic compound pent-4-enoic acid and related non-hypoglycaemic fatty acids. Fatty acid oxidation

1968 ◽  
Vol 110 (3) ◽  
pp. 511-519 ◽  
Author(s):  
A. E. Senior ◽  
B. Robson ◽  
H. S. A. Sherratt
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Saturated Fatty Acids ◽  
Chain Fatty Acid ◽  
Enoic Acid ◽  
Acid Oxidation ◽  
Long Chain Fatty Acid ◽  
Cyclopropanecarboxylic Acid ◽  
Long Chain

1. The effects of the hypoglycaemic compound, pent-4-enoic acid, and of four structurally related non-hypoglycaemic compounds (pentanoic acid, pent-2-enoic acid, cyclopropanecarboxylic acid and cyclobutanecarboxylic acid), on the oxidation of saturated fatty acids by rat liver mitochondria were determined. 2. The formation of 14CO2 from [1−14C]palmitate was strongly inhibited by 0·01mm-pent-4-enoic acid. 3. The inhibition of oxygen uptake was less than that of 14CO2 formation, presumably because fumarate was used as a sparker. 4. The oxidation of [1−14C]-butyrate, -octanoate or -laurate was not strongly inhibited by 0·01mm-pent-4-enoic acid. 5. The other four non-hypoglycaemic compounds did not inhibit the oxidation of any saturated fatty acid when tested at 0·01mm concentration, though they all inhibited strongly at 10mm. 6. The oxidation of [1−14C]-myristate and -stearate, but not of [1−14C]decanoate, was strongly inhibited by 0·01mm-pent-4-enoic acid. 7. The oxidation of [1−14C]palmitate was about 50% carnitine-dependent under the experimental conditions used. 8. The percentage inhibition of [1−14C]palmitate oxidation by pent-4-enoic acid was the same whether carnitine was present or not. 9. Acetoacetate formation from saturated fatty acids was inhibited by 0·1mm-cyclopropanecarboxylic acid to a greater extent than their oxidation. 10. The other compounds tested inhibited acetoacetate formation from saturated fatty acids proportionately to the inhibition of oxidation. 11. Possible mechanisms for the inhibition of long-chain fatty acid oxidation by pent-4-enoic acid are discussed. 12. There was a correlation between the ability to inhibit long-chain fatty acid oxidation and hypoglycaemic activity in this series of compounds.

The Very-Long-Chain Fatty Acid Synthase Is Inhibited by Chloroacetamides

2004 ◽  
Vol 59 (7-8) ◽  
pp. 549-553 ◽  
Author(s):  
Thomas Götz ◽  
Peter Böger
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Chain Fatty Acid ◽  
Long Chain Fatty Acids ◽  
Irreversible Binding ◽  
Long Chain Fatty Acid ◽  
Malonyl Coa ◽  
Elongation Step ◽  
Long Chain

AbstractThe first elongation step to form very-long-chain fatty acids (VLCFAs) is catalyzed by the VLCFA-synthase. CoA-activated fatty acids react with malonyl-CoA to condense a C2-unit. As shown with recombinant enzyme this reaction is specifically inhibited by chloroacetamide herbicides. The inhibition is alleviated when the inhibitor (e.g. metazachlor) is incubated together with adequate concentrations of the substrate (e.g. oleoyl-CoA). Malonyl-CoA has no influence. However, once a chloroacetamide has been tightly bound to the synthase after an appropriate time it cannot be displaced anymore by the substrate. In contrast, oleoyl- CoA, is easily removed from the synthase by metazachlor. The irreversible binding of the chloroacetamides and their competition with the substrate explains the very low half-inhibition values of 10-8 м and below. Chiral chloroacetamides like metolachlor or dimethenamid give identical results. However, only the (S)-enantiomers are active.

The effect of a blend of dietary unesterified and saturated long-chain fatty acids on the performance of dairy cows in mid-lactation

1990 ◽  
Vol 41 (1) ◽  
pp. 129 ◽  
Author(s):  
KR King ◽  
CR Stockdale ◽  
TE Trigg
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Dairy Cows ◽  
Milk Fat ◽  
Chain Fatty Acid ◽  
Long Chain Fatty Acids ◽  
Long Chain Fatty Acid ◽  
Long Chain ◽  
Chain Fatty Acids

This experiment studied the effects of feeding a supplement of a blend of unesterified and saturated long-chain fatty acids on the productivity of dairy cows in mid-lactation. Twenty-three cows in their fourth month of lactation were individually fed ad libitum, a mixed balanced ration based on maize silage, lucerne hay and rolled grain. Varying quantities, up to 1020 g cow-1 day-1 of the fatty acid supplement, were mixed into the ration. Yields of milk and milk products were linearly related to total long-chain fatty acid intake. Milk fat content increased linearly while milk protein content averaged 3.59 (s.d. � 0.15)%. The marginal returns from feeding 1 kg of the supplement were 3.3 kg milk, 0.33 kg fat and 0.07 kg protein. The proportions of C 10:0, C12:0 and C 14:0 fatty acids in milk were decreased, while those of C 18:0 and C18:1 were increased as the result of feeding long-chain fatty acids. The concentration of lipid in plasma was increased, but acetate and D-(3)-hydroxybutyrate levels in blood remained unchanged with increased levels of dietary long-chain fatty acid. Efficiency of milk production was increased by 11% from feeding 1 kg of the supplement. In vivo digestibilities of dry matter, neutral and acid detergent fibres, and dietary long-chain fatty acids were unaffected by supplement.

Sterol and fatty acid composition of four marine haptophycean algae

1981 ◽  
Vol 61 (2) ◽  
pp. 509-527 ◽  
Author(s):  
J. K. Volkman ◽  
D. J. Smith ◽  
G. Eglinton ◽  
T. E. V. Forsberg ◽  
E. D. S. Corner
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Isochrysis Galbana ◽  
Chain Fatty Acid ◽  
Gas Chromatography Mass Spectrometry ◽  
Long Chain Fatty Acid ◽  
Sterol Esters ◽  
Unsaturated Ketones ◽  
Alkenoic Acid ◽  
Long Chain

The lipids of four marine coccolithophorids (class Haptophyceae),Emiliania huxleyi, Hymenomonas carterae, Isochrysis galbanaandCrystallolithus hyalinus, were examined by capillary gas chromatography-mass spectrometry. Fatty acids ranged from C14to C22and were predominantly of even chain length. The major acids were polyunsaturated C18acids, 22:6 and either 14:0 or 16:0. C20fatty acids were of low abundance. Significant amounts of octadecapentaenoic acid (18:5), previously thought to be unique to dinoflagellates, were identified in three of the algae. A small amount of a di-unsaturated C36 w-alkenoic acid was identified inE. huxleyi, which is the first report of such a long-chain fatty acid in any alga. Traces of wax esters, which are reportedly uncommon inalgae, were found in three of the species. The sterol distributions were very simple, with two or three compounds accounting for > 99% of the total sterols. In each case, the major component was 24-methylcholesta-5,22E-dien-3β-ol.H. carteraeandC. hyalinusalso contained 24-ethylcholesta-5,22E-dien-3β-ol and significant amounts of cholest-5-en-3β-ol were found inE. huxleyiandI. galbana. An unusual sterol, 23,24-dimethylcholesta-5,22E-dien-3β-ol, was identified inH. carterae. These sterols were mostly non-esterified although small amounts of sterol esters were identified inE. huxleyi. The lipid composition ofE. huxleyiis distinctive in that it contains, in addition to the C36fatty acid, novel C37–C39unsaturated ketones and C31–C38alkenes. Of the other coccolithophorids onlyI. galbanacontained small quantities of one of the C3lalkenes.

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