Fatty acyl composition

A second important feature worth emphasizing is that the proton leak is affected by the lipid composition of the inner mitochondrial membrane. In general, the fatty acyl chains of phospholipid components of membranes can vary in their degree of unsaturation. The proton leak increases with the incorporation of polyunsaturated fatty acids (FAs) the greater the number of double bonds, the greater the proton leak (Hulbert and Else, 2000). As we shall note in the chapter on temperature relations, fatty acyl composition of membranes, including the inner mitochondrial membranes, changes in various... 

Liu S, Baracos VE, Quinney HA, Clandinin MT. Dietary omega-3 and polyunsaturated fatty acids modify fatty acyl composition and insulin binding in skeletal-muscle sarcolemma. Biochem. J. 1994 299(Pt 3) 831-837. 

TABLE 6. Acyl and Triacylglycerol Composition in mol% of Soybean Oils Having a Wide Range of Fatty Acyl Compositions (48, 49). 

Chow SC, Sisfontes L, Jondal M, Bjorkhem I. Modification of membrane phospholipid fatty acyl composition in a leukemic T cell hne effects on receptor mediated intracellular Ca increase. Biochim Biophys Acta 1991 1092 358-366. 

Tab. 1 Changes in fatty acyl composition [mol%] of pea thylakoid membranes and motion of 16-doxyl stearate resulting from hydrogenation in the presence of palladium—alizarin catalyst.

Fatty acid auxotrophs of cerevlslae have been extensively utilized to probe relationships between fatty acid unsaturation and enzymic activity. A major area of Investigation has been elucidation of the bases for loss of oxidative phosphorylation by yeast cultures characterized by less than ca. 20-30% unsaturated fatty acid (42-44). Much reduced or no activity In mitochondrial membranes with highly saturated fatty acyl compositions has been documented for cytochromes a, a3, b and c, mitochondrial ATPase, succinate oxidase and NADH oxidase (45-47). Fatty acids apparently mediate many mitochondrial functions... 

Nutrient and Fatty Acyl Compositions of Pelleted Diets... 

A relevant question then as a consequence of this work is whether human infants given formulas containing low levels of n-3 fatty acids may have functional losses in spatial task performance. Lx)sses in brain DHA and considerable elevations in 22 5n-6 have been observed in human infants after formula feeding (45,46). The magnitude of these brain fatty acyl compositional changes is not of the magnitude produced in this work in which the diets were nearly devoid of n-3 fatty acids. 

Stable Isotope Administration. The biosynthesis of I. penne 11 i i glucose esters was investigated using deuterium labeled precursors. Compound leaves of L. pennellii were removed and briefly rinsed in 100% EtOH before precursor administration. The preincubation sample of the trichome exudate was saved to establish fatty acyl composition prior to precursor feeding its removal served to increase the proportion of labeled glucose esters after precursor incubations. 

Unfortunately, potential applications regarding mixture analysis are impaired by (i) the overlap between peaks resulting from differences in the fatty acyl composition and (ii) the superposition of H and Na adducts. For instance, the Na adduct of PC 16 0/18 1 and the H adduct of PC 16 0/20 4 result in the same m/z ratio. An initial attempt to overcome this problem involved digesting the PC with phospholipase C (PLC), an enzyme that generates the corresponding DAGs... 

MALDI-TOF-MS has also shown great promise with regards to the determination of enzyme activities. For instance, it was shown that the activity of phospholipase A2 (PIA2), which cleaves the fatty acyl residue in sn-2 position of PL, can be easily monitored since both the substrate (PC) and the reaction product (LPC) are simultaneously detectable in the mass spectrum [94]. Because of its lower molecular weight, LPC is more sensitively detected than is PC, and this represents a considerable advantage when only low-level enzyme activities are to be determined. Of course, the most important advantage of this assay is that there is no need to label the substrate, and all PC species can be used independent of their fatty acyl compositions. This approach was also applied to monitor the impact of compounds with inhibitory effects towards PLA2 [95]. 

The spectrum recorded in the presence of 9-AA (b) is much simpler to interpret because there are primarily the proton adducts of the individual PC species. This enables the direct assignments of the m/z values to the fatty acyl compositions, while this is much more difficult using DHB that leads to a mixture between and Na adducts. 

Of course, many characteristic dyes available allow the specific staining of selected GPL classes [11]. However, the majority of these dyes are specific for the headgroup (for instance, free amino residues can be stained by ninhydrin) and, thus, information about the lipid class but neither about the fatty acyl composition nor the linkage type is available. 

Stiibiger and colleagues [36] used a similar approach (in addition to the MS analysis of lipid species subsequent to reelution from the TLC plate) to screen the compositions of various neutral (e.g., triacylglycerols) and polar (e.g., GPL and glyc-erosphingolipids [GSL]) lipid classes derived from crude lipid extracts of human plasma as well as soybean lecithin. These authors [36] have also provided evidence that combining TLC/MS with post source decay (PSD) MALDl MS helps to address structural problems such as the detailed fatty acyl composition and the differentiation of positional isomers sn- vs. sn- I). PSD may be considered an MS/MS-Uke experiment that can be performed on all TOP instruments equipped with a reflectron [20] but without the need of a dedicated collision ceU. About 70 different lipid species could be detected in just 50 jL of human blood plasma. 

Canola Bacteria Napin/ CrtB Phytoene synthase Fatty acyl composition Higher 18 1 (oleic acid) component [122]... 

This discrepancy could arise from the fact that in the enzyme-lyposome complexes HBD activity is poorly affected by the fatty acyl composition of the phospholipids, while it is quite sensitive to changes in the fatty acyl composition of the phospholipids within the membrane. 

Table 9.4 Effect of A9- and A12-cyclopropene fatty acids on the fatty acyl composition of Rhodosporidium toruloides (from Moreton, 1988a,b)...

Table 9.5 Fatty acyl composition of triacylglycerols from Candida curvatalApiotrichum curvatum wild type (WT) strain, an unsaturated fatty acid auxotrophic mutant (Ufa 33), a revertant mutant (R22.72) and a hybrid derived from Ufa 33 (F33.10) compared to cocoa butter fatty acids...

Huo, T., Ferruzzi, M.G., Schwartz, S.J. FaUla, M.L. (2007). Impact of fatty acyl composition and quantity of triglycerides on bioaccessibUity of dietary carotenoids. Journal of Agricultural and... 

The acyl composition of somatic embryos from B. campestris cultured in 10% sucrose, was similar to that found in immature zygotic embryos in vivo and in mature seed. Of note, somatic embryos also accumulated the very long chain seed-specific , eicosenoic and erucic adds [71]. It has also been reported that zygotic embryos of B. juncea, cultured in vitro accumulate hpids with a fatty acyl composition similar to the embryo in vivo [74]. 

Esch, S.W., Tamura, P., Sparks, A.A., Roth, M.R., Devaiah, S.P., Heinz, E., Wang, X., Williams, T.D. and Welti, R. (2007) Rapid characterization of the fatty acyl composition of complex lipids by collision-induced dissociation time-of-flight mass spectrometry. J. Lipid Res. 48, 235-241. 

The relationship between the fatty acid composition of the membrane lipids and an organism s ethanol tolerance also has been investigated using mutants of E. coli. The membrane fatty acyl composition of E. coli is easily manipulated using mutants... 

Lipids present in cell membranes are usually heterogenous with respect to fatty acyl composition. The structure and properties of 1,2-diacyl-L-phosphatidylcholine containing identical fatty acid chains have been studied in detail. The glycerol carbon atoms are orientated approximately perpendicular to layer plane. The initial part of the fatty acid at the 2-position extends layer-parallel but bends off at the second Carbon atom. This gives rise to an apparent difference in chain length... 

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