Fatty acids proton production

In positive ion mode, the characteristic peaks representative of the binding media were fatty acids from lead soaps (of palmitic acid at m/z 461 463 and of stearic acid at m/z 489 491). Other peaks corresponding to mono- and diacylglycerol cations, protonated stearic acid or its acylium ions could be found in the spectra of the reference products but not in the paint sample. The spectrum of lead white egg tempera paint exhibits peaks of phosphocholine (m/z 184) and protonated ketocholesterol (m/z 401). These peaks were not found in the spectrum from the cross-section. In negative ion mode, the spectrum of the oil... 

Protons attached to the C atoms of the 1,2,4-trioxolane moiety of FOZs have chemical shifts at distinctly lower field than alcohols, ethers or esters. For example, the chemical shifts of the ozonide product in equation 100 (Section Vin.C.b.a) are S (CDCI3) 5.7 ppm for the H atoms of the trioxolane partial structure, and 4.1 ppm for the protons at the heads of the other ether bridge . Measurement of the rate of disappearance of these signals can be applied in kinetic studies of modifications in the ozonide structure. The course of ozonization of the methyl esters of the fatty acids of sunflower oil can be followed by observing in H and C NMR spectra the gradual disappearance of the olefinic peaks and the appearance of the 3,5-dialkyl-1,2,4-trioxolane peaks. Formation of a small amount of aldehyde, which at the end of the process turns into carboxylic acid, is also observed . 

Figure 8.3 Metabolism of tetrachloromethane. Upon metabolic activation a CCI3 radical is formed. This radical extracts protons from unsaturated fatty acids to form a free fatty-acid radical. This leads to diene conjugates. At the same time, O2 forms a hydroperoxide with the C radical. Upon its decomposition, malondialdehyde and other disintegration products are formed. In contrast, the CC13 radical is converted to chloroform, which undergoes further oxidative metabolism. (Reprinted from H. M. Bolt and J. T. Borlak, in Toxicology, pp. 645-657, copyright 1999, with permission from Elsevier.)...

In animal fermentations, an organic molecule (e.g., pyruvate) serves as a terminal proton and electron acceptor, forming an organic end product (e.g., lactate). In contrast, 02 is required as a terminal acceptor for the complete oxidation of substrates such as glucose, glycogen, fatty acids, or amino acids. As discussed in chapter 3, 02 was not always available as one of the substrates for oxidative metabolism and organisms in primordial times had to rely on anaerobic metabolic processes. 

Free fatty acid (FFA) are the main substances used as fuel by the myocardium, normally preferentially over glucose. However, they need more oxygen than glucose to produce equal amounts of ATP. Moreover, their increased oxidation concomitantly results into a diminution of the oxidation of glucose with an increase of lactic acid production and protons, which in their turn need greater ATP consumption. Thus, cardiac... 

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