Kinetic Studies on the Chain Length Specificity of Long Chain Acyl Coenzyme A Synthetase from Rat Liver Microsomes

Suzue, Ginzaburo; Marcel, Yves L.

doi:10.1016/s0021-9258(19)44654-1

Cited by 38 publications

(3 citation statements)

References 14 publications

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“…It is well known that the formation of fatty acid thiol esters is necessary during the esterification process. An explanation for the low re-uptake of some fatty acids could be their low activation in adipose tissue [41]. Indeed, the activation of fatty acids is brought about by long-chain acyl-CoA synthetase, which exhibits substrate specificity [42].…”

Section: Discussionmentioning

confidence: 99%

Net release of individual fatty acids from white adipose tissue during lipolysis in vitro: evidence for selective fatty acid re-uptake

Raclot¹,

Oudart

2000

Biochemical Journal

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During lipolysis, adipose tissue triacylglycerols (TAG) undergo concurrent breakdown and synthesis because some of the newly hydrolysed and released non-esterified ('free') fatty acids (NEFA) can subsequently be taken up and re-esterified. The present study examines whether and how the release of individual fatty acids is affected by the re-uptake of some of the newly hydrolysed fatty acids in vitro during lipolysis. To alter fatty acid release and re-uptake, adipose tissue fragments and isolated adipocytes from rats were incubated under various conditions, i.e. several cell concentrations or adipose fragment quantities, with or without glucose. In the various conditions tested, the NEFA/glycerol molar ratio ranged from 1.5 to 2.9. Whatever the incubation conditions, including those resulting in very low, medium or high fatty acid re-uptake (as assessed by the NEFA/glycerol ratio), the percentage weight of fatty acids in NEFA was significantly different from that in TAG for 20-24 of the 35 fatty acids that were considered. Thus the greater the fatty acid re-uptake, the higher the proportion of polyunsaturated fatty acids and the lower the proportion of long-chain saturated and monounsaturated fatty acids in NEFA. Moreover, the relative mobilization (%NEFA/%TAG) of the least readily mobilized fatty acid (C(22:1,n-11)) was 6.2-fold lower than that of the most readily mobilized fatty acid (C(20:5,n-3)) under conditions of very low fatty acid re-uptake, and 14.8-fold lower under conditions of high fatty acid re-uptake, indicating a widening of the range of relative mobilizations. We conclude that the composition of the NEFA pool is affected by the rate of fatty acid re-uptake. This provides strong evidence for the selective re-uptake of adipose tissue fatty acids during lipolysis.

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Section: Discussionmentioning

confidence: 99%

Net release of individual fatty acids from white adipose tissue during lipolysis in vitro: evidence for selective fatty acid re-uptake

Raclot¹,

Oudart

2000

Biochemical Journal

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“…These substrates usually are added to assays as complexes with proteins containing nonspecific sites for binding of hydrophobic compounds, or they are added as salt suspensions [e.g., see Aas (1971), Farstad et al (1967), Pande & Mead (1968), and Pande (1972)]. Detergents are added to assays in some instances for the purpose of dispersing the water-insoluble substrates (Bar-Tana et al, 1971; Tanaka et al, 1979;Suzue & Marcel, 1972). The data are treated as if substrates added by these methods distribute homogeneously in the assay system.…”

mentioning

confidence: 99%

Fatty acids bound to unilamellar lipid vesicles as substrates for microsomal acyl-CoA ligase

Noy¹,

Zakim²

1985

Biochemistry

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Palmitate incorporated into single-layered vesicles of phosphatidylcholine was used as a substrate for palmitoyl coenzyme A ligase (palmitoyl-CoA ligase) in microsomes from rat liver. This was done in order to avoid the use of detergents for dispersal of the water-insoluble palmitate and the possibility of precipitating palmitate added to the aqueous assay as a salt suspension. The activity of the ligase measured when palmitate was added to assays as a component of phospholipid vesicles was 10-40-fold greater vs. activities reported in the literature using other methods for adding fatty acids to the assay system. Phospholipids, however, had no direct effect on the activity of palmitoyl-CoA ligase. The data indicate, therefore, that the activity of this enzyme has been underestimated because of the manner in which fatty acid was added to the assay, which has a significant effect on the activity of the ligase. It is shown too that the rate of spontaneous transfer of palmitate from unilamellar vesicles of phosphatidylcholine to microsomes via a hydrated intermediate is far more rapid than the inherent catalytic activity of the fatty acyl-CoA ligase. The data also suggest that the membrane-associated pool of fatty acid and not fatty acid in the aqueous phase of the assay is the pool of substrate interacting with the ligase.

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“…This is consistent with the findings of Pai et al ( 32 ) in cultured rat hepatocytes, where SA was present in a greater proportion in NEFA than other FAs. Bruce et al ( 34 ) concluded that the conversion of stearate into stearoyl-CoA may be a rate-limiting step, perhaps due to poor metabolism of stearate by the long-chain acyl-CoA synthase ( 38 ). This is one possible explanation why SA is increasingly present as a NEFA in the BFH12.…”

Section: Discussionmentioning

confidence: 99%

The Bovine Hepatic Cell Line BFH12 as a Possible Model for Hepatosteatosis in Dairy Cows

et al. 2022

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Hepatosteatosis is a common metabolic disorder of dairy cows, especially during early lactation. Currently, there are a few models of bovine hepatic steatosis available, including primary hepatocytes, liver slices, and animal models. Studies that elucidate the influence of single fatty acids on lipid classes, fatty acid pattern, gene expression, and phenotypic changes are still limited. Hence, we investigated the suitability of the fetal bovine hepatocyte-derived cell line BFH12 as a model for hepatosteatosis. To create a steatotic environment, we treated BFH12 with stearic acid, palmitic acid, or oleic acid in non-toxic doses. Thin-layer chromatography and gas chromatography were used to analyze lipid classes and fatty acid pattern, and qPCR was used to quantify gene expression of relevant target genes. Lipid droplets were visualized with confocal laser scanning microscopy and evaluated for number and size. Treatment with oleic acid increased triglycerides, as well as lipid droplet count per cell and upregulated carnitine palmitoyl transferase 1, which correlates with findings of in vivo models. Oleic acid was largely incorporated into triglycerides, phospholipids, and non-esterified fatty acids. Stearic acid was found mainly in non-esterified fatty acids and triglycerides, whereas palmitic acid was mainly desaturated to palmitoleic acid. All three fatty acids downregulated stearyl-CoA-desaturase 1. In conclusion, BFH12 can acquire a steatotic phenotype by incorporating and accumulating fatty acids. Oleic acid is particularly suitable to produce hepatosteatosis. Therefore, BFH12 may be a useful in vitro model to study bovine hepatosteatosis and its underlying molecular mechanisms.

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Kinetic Studies on the Chain Length Specificity of Long Chain Acyl Coenzyme A Synthetase from Rat Liver Microsomes

Cited by 38 publications

References 14 publications

Net release of individual fatty acids from white adipose tissue during lipolysis in vitro: evidence for selective fatty acid re-uptake

Net release of individual fatty acids from white adipose tissue during lipolysis in vitro: evidence for selective fatty acid re-uptake

Fatty acids bound to unilamellar lipid vesicles as substrates for microsomal acyl-CoA ligase

The Bovine Hepatic Cell Line BFH12 as a Possible Model for Hepatosteatosis in Dairy Cows

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