Journal of Lipid Research, Vol 31, 889-897, Copyright © 1990 by Lipid Research, Inc.
Inhibition of lipolysis by hydrocarbons and fatty alcohols
GC Ferreira and JS Patton
Department of Biological Chemistry, School of Medicine, Johns Hopkins University, Baltimore, MD 21205.
The hydrolysis of long-chain triglyceride by pancreatic lipase (EC 3.1.1.3)
is inhibited by hydrophobic solutes that are dissolved in the fat. Solutes
tested included n-alkanes (C10-C16), aromatic and chlorinated aromatic
hydrocarbons (including a PCB and DDT), n-alcohols (C10-C16), and
cholesterol. Except for cholesterol, which stimulated lipolysis at low
concentrations, all compounds produced roughly similar inhibition curves
that followed the pattern of a typical Langmuir adsorption isotherm
(Mattson, F. H., R. A. Volpenhein, and L. Benjamin, 1970. J. Biol. Chem.
245: 5335-5340). According to this interpretation, hydrophobic solutes
dissolved within fat droplets partition between the interior oil phase and
the surface monolayer where lipolysis occurs. Although the aromatic and
chlorinated aromatic hydrocarbons were approximately 25% more inhibitory
than the long-chain aliphatic hydrocarbons, as a single class, hydrocarbons
were 7-10 times weaker inhibitors of lipolysis than fatty alcohols. In
contrast to the alcohols whose inhibitory action may involve several
mechanisms, the hydrocarbons behaved like simple dilution inhibitors; i.e.,
at 50% inhibition the mass ratio of hexadecane to triglyceride was 0.42.
The lack of a chain length effect indicates that the hydrocarbons are not
adsorbed at the interface but interdigitate the triglyceride molecules and
align parallel to the lipid acyl chains. Inhibition by hydrophobic solutes
was not reversed by the presence of 4 mM taurodeoxycholate and pancreatic
procolipase or colipase.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
