Showing papers on "Acyl-CoA published in 1992"
TL;DR: It is proposed that acyl CoA is the donor in inositol acylation of GlcN-PI, and that Gl cN-(acyl-inositol)PI is an obligatory intermediate in GPI synthesis.
81 citations
TL;DR: The data demonstrate that elevation of H2O2 formation by acyl CoA oxidase activity measured in vitro is not necessarily associated with increases in rates of H 2O2 generation in intact perfused liver or in vivo, most likely due to rate-limitation in intact cells by fatty acid supply.
36 citations
TL;DR: Linoleic acid as fatty acid substrate had the highest affinity to acyl-CoA:1-acyl-lysophospholipid acyltransferase with lysoPC as variable substrate, followed by eicosapentaenoic acid (EPA) and arachidonic acid (AA).
Abstract: The activities of acyl-CoA:1-acyl-lysophospholipid acyltransferases (EC 2.3.1.23) have been studied in human platelet lysates by using endogenously formed [14C]acyl-CoA from [14C]fatty acid, ATP and CoA in the presence of 1-acyl-lysophosphatidyl-choline (lysoPC), -ethanolamine (lysoPE), -serine (lysoPS) or -inositol (lysoPI). Linoleic acid as fatty acid substrate had the highest affinity to acyl-CoA:1-acyl-lysophospholipid acyltransferase with lysoPC as variable substrate, followed by eicosapentaenoic acid (EPA) and arachidonic acid (AA). The activity at optimal conditions was 7.4, 7.3 and 7.2 nmol/min per 10(9) platelets with lysoPC as substrate, with linoleic acid, AA and EPA respectively. EPA and AA were incorporated into all lyso-forms. Linoleic acid was also incorporated into lysoPE at a high rate, but less into lysoPS and lysoPI. DHA was incorporated into lysoPC and lysoPE, but only slightly into lysoPI and lysoPS. Whereas incorporation of all fatty acids tested was maximal for lysoPC and lysoPI at 200 and 80 microM respectively, maximal incorporation needed over 500 microM for lysoPE and lysoPS. The optimal concentration for [14C]fatty acid substrates was in the range 15-150 microM for all lysophospholipids. Competition experiments with equimolar concentrations of either lysoPC and lysoPI or lysoPE resulted in formation of [14C]PC almost as if lysoPI or lysoPE were not added to the assay medium.
15 citations
TL;DR: The procedure seems suitable for synthesizing the labeled CoA and carnitine esters from a variety of radioactive fatty acids.
Abstract: Rat liver mitochondrial outer membrane enriched preparations have proven to be a convenient enzyme source for synthesizing coenzyme A (CoA) and carnitine esters of radioactive fatty acids. These membranes are simple to isolate and they retain acyl-CoA ligase and carnitine palmitoyltransferase activities well upon storage. Enzyme purification is not required. A novel aspect of the present procedure is that the same enzymatic incubation step allows both the acyl-CoA and the acylcarnitine esters to be obtained simulataneously when carnitine is present, but produces acyl-CoA ester only when carnitine is not included. Under the conditions described, the conversion of [1-14C]octanoic acid to the respective esters was about 95%; the corresponding figure for [1-14C]palmitic acids was over 70%. The procedure seems suitable for synthesizing the labeled CoA and carnitine esters from a variety of radioactive fatty acids.
7 citations
TL;DR: Results indicate that acyl CoA synthetase for medium-chain fatty acids in rat intestinal mucosa plays a key role in the utilization of medium- chain fatty acids for lipid synthesis, and that it is regulated in a different manner from acyl coenzyme A synthetases for long- Chain fatty acids.
Abstract: A system was developed for assay of acyl coenzyme A (acyl CoA) activity on medium-chain fatty acids in rat intestinal mucosa. Using this system, we compared the characteristics of octanoyl (C8:0) CoA
6 citations
TL;DR: It is apparent that the mitochondrial membrane barrier, which remains intact after sucrose density gradient centrifugation, prevents rapid access of acyl CoA substrates to matrix β-oxidation sites, and intact mitochondria showed little β-Oxidation enzyme activity.
Abstract: Two sites for the β-oxidation of fatty acids in avocado (Persea americana L.) mesocarp exist. One site is the microbody, the other the mitochondrion. It is apparent that the mitochondrial membrane barrier, which remains intact after sucrose density gradient centrifugation, prevents rapid access of acyl CoA substrates to matrix β-oxidation sites. Thus, intact mitochondria showed little β-oxidation enzyme activity. Rupturing of the mitochondrial membrane allowed rapid access of the acyl CoA substrates to matrix sites. Consequently, in ruptured mitochondria, high O2-oxidation enzyme activities were measured. O2 uptake studies further distinguished the two organellar sites of β-oxidation. During palmitoyl CoA oxidation, O2 uptake was reduced by catalase and increased by KCN in the microbodies, whilst mitochondrial O2 uptake was unaffected by catalase and reduced by KCN. This reflected the differing fates of FADH2, produced during the first β-oxidation step, in the two organelles. In addition, only the mitochondrial β-oxidation of fatty acids was carnitine-dependent.
5 citations