Selective enrichment of n−3 polyunsaturated fatty acids with C18–C20 acyl chain length from sardine oil using Pseudomonas fluorescens MTCC 2421 lipase

The synthesis of fatty acids de novo from acetate and the elongation of exogenous satuated fatty acids (C12-C18) by the psychrophilic bacterium Micrococcus cryophilus (A.T.C.C. 15174) grown at 1 or 20 degrees C was investigated. M. cryophilus normally contains only C16 and C18 acyl chains in its phospholipids, and the C18/C16 ratio is altered by changes in growth temperature. The bacterium was shown to regulate strictly its phospholipid acyl chain length and to be capable of directly elongating myristate and palmitate, and possibly laurate, to a mixture of C16 and C18 acyl chains. Retroconversion of stearate into palmitate also occurred. Fatty acid elongation could be distinguished from fatty acid synthesis de novo by the greater sensitivity of fatty acid elongation to inhibition by NaAsO2 under conditions when the supply of ATP and reduced nicotinamide nucleotides was not limiting. It is suggested that phospholipid acyl chain length may be controlled by a membrane-bound elongase enzyme, which interconverts C16 and C18 fatty acids via a C14 intermediate; the activity of the enzyme could be regulated by membrane lipid fluidity.

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Acyl chain length dependency of diacylglycerol cholinephosphotransferase and diacylglycerol ethanolaminephosphotransferase. Effect of different saturated fatty acids at the C-1 or C-2 position of diacylglycerol on solubilized rat liver microsomal enzymes.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(17)34656-2 ◽

1978 ◽

Vol 253 (14) ◽

pp. 5056-5060

Author(s):

K. Morimoto ◽

H. Kanoh

Keyword(s):

Fatty Acids ◽

Chain Length ◽

Rat Liver ◽

Saturated Fatty Acids ◽

Acyl Chain ◽

Microsomal Enzymes ◽

Acyl Chain Length ◽

Liver Microsomal Enzymes

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Different rates of flux through the biosynthetic pathway for long-chain versus very-long-chain sphingolipids

The Journal of Lipid Research ◽

10.1194/jlr.ra120000984 ◽

2020 ◽

Vol 61 (10) ◽

pp. 1341-1346

Author(s):

Iris D. Zelnik ◽

Giora Volpert ◽

Leena E. Viiri ◽

Dimple Kauhanen ◽

Tamar Arazi ◽

...

Keyword(s):

Fatty Acids ◽

Chain Length ◽

Biosynthetic Pathway ◽

Acyl Chain ◽

Degree Of Saturation ◽

Disease States ◽

Acyl Chain Length ◽

Long Chain Base ◽

Acyl Chains ◽

Long Chain

The backbone of all sphingolipids (SLs) is a sphingoid long-chain base (LCB) to which a fatty acid is N-acylated. Considerable variability exists in the chain length and degree of saturation of both of these hydrophobic chains, and recent work has implicated ceramides with different LCBs and N-acyl chains in distinct biological processes; moreover, they may play different roles in disease states and possibly even act as prognostic markers. We now demonstrate that the half-life, or turnover rate, of ceramides containing diverse N-acyl chains is different. By means of a pulse-labeling protocol using stable-isotope, deuterated free fatty acids, and following their incorporation into ceramide and downstream SLs, we show that very-long-chain (VLC) ceramides containing C24:0 or C24:1 fatty acids turn over much more rapidly than long-chain (LC) ceramides containing C16:0 or C18:0 fatty acids due to the more rapid metabolism of the former into VLC sphingomyelin and VLC hexosylceramide. In contrast, d16:1 and d18:1 ceramides show similar rates of turnover, indicating that the length of the sphingoid LCB does not influence the flux of ceramides through the biosynthetic pathway. Together, these data demonstrate that the N-acyl chain length of SLs may not only affect membrane biophysical properties but also influence the rate of metabolism of SLs so as to regulate their levels and perhaps their biological functions.

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