scholarly journals Peroxisomal β-oxidation of long-chain fatty acids possessing different extents of unsaturation

1987 ◽  
Vol 247 (3) ◽  
pp. 531-535 ◽  
Author(s):  
R Hovik ◽  
H Osmundsen
Keyword(s):  
Fatty Acids ◽  
Substrate Inhibition ◽  
Fatty Acyl ◽  
Long Chain Fatty Acids ◽  
Beta Oxidation ◽  
Long Chain ◽  
Myristoyl Coa ◽  
Chain Fatty Acids

Rates of peroxisomal beta-oxidation were measured as fatty acyl-CoA-dependent NAD+ reduction, by using solubilized peroxisomal fractions isolated from livers of rats treated with clofibrate. Medium- to long-chain saturated fatty acyl-CoA esters as well as long-chain polyunsaturated fatty acyl-CoA esters were used. Peroxisomal beta-oxidation shows optimal specificity towards long-chain polyunsaturated acyl-CoA esters. Eicosa-8,11,14-trienoyl-CoA, eicosa-11,14,17-trienoyl-CoA and docosa-7,10,13,16-tetraenoyl-CoA all gave Vmax. values of about 150% of that obtained with palmitoyl-CoA. The Km values obtained with these fatty acyl-CoA esters were 17 +/- 6, 13 +/- 4 and 22 +/- 3 microM respectively, which are in the same range as the value for palmitoyl-CoA (13.8 +/- 1 microM). Myristoyl-CoA gave the higher Vmax. (110% of the palmitoyl-CoA value) of the saturated fatty acyl-CoAs tested. Substrate inhibition was mostly observed with acyl-CoA esters giving Vmax. values higher than 50% of that given by palmitoyl-CoA.

Inhibitory effects of long-chain fatty acids on VFA degradation and β-oxidation

2003 ◽  
Vol 47 (10) ◽  
pp. 139-146 ◽  
Author(s):  
H.-S. Shin ◽  
S.-H. Kim ◽  
C.-Y. Lee ◽  
S.-Y. Nam
Keyword(s):  
Fatty Acids ◽  
Methane Production ◽  
Substrate Inhibition ◽  
Long Chain Fatty Acids ◽  
Inhibitory Effects ◽  
Inhibition Model ◽  
Propionate Degradation ◽  
Acetate Degradation ◽  
Long Chain ◽  
Chain Fatty Acids

The inhibitory effects of major long-chain fatty acids (LCFA), which have 16 or 18 carbons, not only on acetate degradation, but also on propionate degradation and β-oxidation were examined in anaerobic serum bottle tests at 35°C with the acclimated granular sludges. A modified Gompertz equation described cumulative methane production to assess the rates of VFA degradation and β-oxidation, which were applied to a simplified noncompetitive model and a simplified substrate inhibition model, respectively. The specific methane production rates on acetate decreased as LCFA concentration increased, which was in good agreement with the noncompetitive inhibition model. Unsaturated oleate (C18:1) and linoleate (C18:2) were more inhibitory than saturated stearate (C18:0) and palmitate (C16:0) on acetate degradation. LCFA inhibition on propionate degradation was similar to that for acetate; however, propionate degradation was less inhibited than acetate degradation. β-oxidation was the rate-limiting step in LCFA degradation in most cases. As LCFA concentration increased, β-oxidation rate reached the maximum value, and then decreased, which confirmed the substrate inhibition of LCFA. Oleate, the most abundant LCFA in wastewater, could be degraded more quickly than saturated LCFA containing the same or even less carbon in spite of relatively high toxicity on acetate degradation.

Candida albicans fatty acyl-CoA synthetase, CaFaa4p, is involved in the uptake of exogenous long-chain fatty acids and cell activity in the biofilm

2017 ◽  
Vol 64 (2) ◽  
pp. 429-441 ◽  
Author(s):  
Kengo Tejima ◽  
Masanori Ishiai ◽  
Somay O. Murayama ◽  
Shun Iwatani ◽  
Susumu Kajiwara
Keyword(s):  
Fatty Acids ◽  
Candida Albicans ◽  
Cell Activity ◽  
Fatty Acyl ◽  
Long Chain Fatty Acids ◽  
Long Chain ◽  
Chain Fatty Acids

scholarly journals Transmembrane Movement of Exogenous Long-Chain Fatty Acids: Proteins, Enzymes, and Vectorial Esterification

2003 ◽  
Vol 67 (3) ◽  
pp. 454-472 ◽  
Author(s):  
Paul N. Black ◽  
Concetta C. DiRusso
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Molecular Genetics ◽  
Fatty Acyl ◽  
Model Systems ◽  
Fatty Acid Transport ◽  
Long Chain Fatty Acids ◽  
Acid Transport ◽  
Long Chain ◽  
Chain Fatty Acids

SUMMARY The processes that govern the regulated transport of long-chain fatty acids across the plasma membrane are quite distinct compared to counterparts involved in the transport of hydrophilic solutes such as sugars and amino acids. These differences stem from the unique physical and chemical properties of long-chain fatty acids. To date, several distinct classes of proteins have been shown to participate in the transport of exogenous long-chain fatty acids across the membrane. More recent work is consistent with the hypothesis that in addition to the role played by proteins in this process, there is a diffusional component which must also be considered. Central to the development of this hypothesis are the appropriate experimental systems, which can be manipulated using the tools of molecular genetics. Escherichia coli and Saccharomyces cerevisiae are ideally suited as model systems to study this process in that both (i) exhibit saturable long-chain fatty acid transport at low ligand concentrations, (ii) have specific membrane-bound and membrane-associated proteins that are components of the transport apparatus, and (iii) can be easily manipulated using the tools of molecular genetics. In both systems, central players in the process of fatty acid transport are fatty acid transport proteins (FadL or Fat1p) and fatty acyl coenzyme A (CoA) synthetase (FACS; fatty acid CoA ligase [AMP forming] [EC 6.2.1.3]). FACS appears to function in concert with FadL (bacteria) or Fat1p (yeast) in the conversion of the free fatty acid to CoA thioesters concomitant with transport, thereby rendering this process unidirectional. This process of trapping transported fatty acids represents one fundamental mechanism operational in the transport of exogenous fatty acids.

scholarly journals Comparative biochemistry of β-oxidation. An investigation into the abilities of isolated heart mitochondria of various animal species to oxidize long-chain fatty acids, including the C22:1 monoenes

1978 ◽  
Vol 174 (2) ◽  
pp. 379-386 ◽  
Author(s):  
H Osmundsen ◽  
J Bremer
Keyword(s):  
Fatty Acids ◽  
Animal Species ◽  
Species Differences ◽  
Isolated Heart ◽  
Tricarboxylic Acid Cycle ◽  
Heart Mitochondria ◽  
Long Chain Fatty Acids ◽  
Beta Oxidation ◽  
Long Chain ◽  
Chain Fatty Acids

Rates of acylcarnitine oxidation by isolated heart mitochondria from various animal species were measured polarographically, and by using a spectrophotometric assay [see Osmundsen & Bremer (1977) Biochem. J. 164, 621-633]. Polarographic measurements do not give a correct guide to abilities to beta-oxidize very-long-chain acylcarnitines, in particular C22:1 fatty acylcarnitines. 2. No significant species differences were detected in the abilities to beta-oxidize various C22:1 fatty acylcarnitines. Significant species differences were, however, detected when rates of beta-oxidation were correlated with rates of respiration brought about by very-long-chain acylcarnitines. We concluded that some aspects of oxidative metabolism (possibly the oxidation of tricarboxylic acid-cycle intermediates) are inhibited by very-long-chain fatty acids in some species (e.g. the rat and the cat but not in others (e.g. the pig and the rabbit). 3. It is proposed that the pattern of variation of rates of oxidation of various acylcarnitines (as measured spectrophotometrically) of various chain lengths can be used as a guide to the chain-length specificities of the acyl-CoA dehydrogenases of beta-oxidation (EC 1.3.99.3).

Sign in / Sign up

Export Citation Format

Share Document