The kinetics of activation of saturated fatty acids by long chain acyl-CoA synthetase from rat liver microsomes has been studied with a method of selective extraction of free fatty acids based on the insolubility of acyl-CoA in diethyl ether. Saturated fatty acids with a chain length ranging from Cl* to Co were assayed at concentrations varying from 0.5 to 10 PM. Under these conditions, Vm,, is...

Very long chain acyl-CoA dehydrogenase is a newly characterised enzyme in mitochondrial fatty acid oxidation. A girl who presented on the second day of life with a sudden and severe illness due to deficiency of this enzyme is reported. There is evidence that some children (and perhaps all) originally diagnosed with a deficiency of long-chain acyl-CoA dehydrogenase, in fact, have a defect involv...

The enzymes catalysing the initial stage of the 8-oxidation of fatty acids, the acyl-CoA synthetases, have been classified into four groups based on specificity. These are: the short-chain (acetyl-CoA synthetase; EC 6.2.1 .l), medium-chain (butyryl-CoA synthetase; EC 6.2.1.2) and the long-chain fatty acyl-CoA synthetase (acyl-CoA synthetase; EC 6.2.1.3), which are ATP-dependent and follow the r...

[19F]-1H heteronuclear difference nuclear Overhauser effect experiments are performed on a sample of 5,5-difluorohexanoyl acyl carrier protein from Escherichia coli. Interaction of the fluorines at the 5-position of the acyl chain with protons on methyl groups of isoleucine 54 and alanine 59 is clearly indicated. The covalent attachment of the acyl chain via a prosthetic group to serine 36 and ...

Peroxisomes function in beta-oxidation of very long and long-chain fatty acids, dicarboxylic fatty acids, bile acid intermediates, prostaglandins, leukotrienes, thromboxanes, pristanic acid, and xenobiotic carboxylic acids. These lipids are mainly chain-shortened for excretion as the carboxylic acids or transported to mitochondria for further metabolism. Several of these carboxylic acids are sl...

In order to probe the active-site structure of human milk bile-salt-activated lipase (BAL), the kinetics of the BAL-catalysed reaction were studied using monoesters as substrates. Among the fatty acyl chains, ranging from C8 to C16 of monoacylglycerols in a single equimolar assay mixture, there was a consistent trend of increased reactivity with decreased fatty-acyl-chain length for both the ba...

A cerulenin insensitive 3-ketoacyl-acyl carrier protein synthase has been assayed in extracts of spinach (Spinacia oleracea) leaf. The enzyme was active in the 40 to 80% ammonium sulfate precipitate of whole leaf homogenates and catalyzed the synthesis of acetoacetyl-acyl carrier protein. This condensation reaction was five-fold faster than acetyl-CoA:acyl carrier protein transacylase, and the ...

The possibility of a regulatory role of long-chain acyl-CoAs was studied in a system synthesizing palmitoyl-CoA and stearoyl-CoA in vitro. This system contained acetyl-CoA carboxylase (yeast), fatty acid synthetase (yeast) and lipid membranes as acceptors for the long-chain acyl-CoA compounds. In this system acetyl-CoA carboxylase is controlled by long-chain acyl-CoAs, whereas this is not true ...

Many Gram-negative bacteria use quorum sensing (QS) to regulate expression of multiple genes, by utilizing small diffusible signalling molecules called N-acyl homoserine lactones (acyl-HSLs). Serratia sp. ATCC 39006 produces the red pigment prodigiosin under QS control, in response to the short-chain signal C4-HSL. In this study, we have demonstrated that an acyl-HSL-deficient mutant can be use...

The membrane vertical phase separation hypothesis predicts that a decrease in plasma membrane acyl chain order will increase major histocompatibility complex (MHC) class I surface expression. The hypothesis is based on modification of plasma membrane acyl chain order in cell culture and has not been tested in vivo. In the present study, we isolated splenic B cells from C57/BL6 mice fed either a...