Acid profile

Plant proteins from single sources, such as soybean meal, may be abundant in specific amino acids that are deficient in some cereal grains. Thus a combination of soybean meal and com with theh amino acid symbiosis may provide an exceUent amino acid profile for dogs. Plant protein mixtures alone do not meet the amino acid needs for cats, because taurine [107-35-7] is not generaUy present in plant proteins. 

Milk and egg products are highly desired in pet foods since they supply the highest quaHty amino acid profiles with nearly 100% digestibiHty. Most milk protein concentrates are used for human foods, but some are available to pets (see Milk and milk products). An enormous quantity of whole eggs (qv) derived from egg graders, egg breakers, and hatchery operations are handled as dehydrated, Hquid, or frozen ingredients. 

LPC Product Quality. Table 10 gives approximate analyses of several LPC products. Amino acid analyses of LPC products have been pubhshed including those from alfalfa, wheat leaf, barley, and lupin (101) soybean, sugar beet, and tobacco (102) Pro-Xan LPC products (100,103) and for a variety of other crop plants (104,105). The composition of LPCs varies widely depending on the raw materials and processes used. Amino acid profiles are generally satisfactory except for low sulfur amino acid contents, ie, cystine and methionine. 

Amino acid profiles of FPC ate excellent and compare favorably with whole egg except for tryptophan and lysiae (140). Hake and Atlantic FPCs prepared by isoptopanol extraction have PERs of 3.29 and 3.05, respectively, as compared with 3.0 for caseia (140). Numerous human feeding studies have been conducted with FPC. The results iadicate that high quaUty, bland FPC products can be used as proteia supplemeats but they ate aot suitable for use as a sole source of proteia. 

Nitration of 3,5-dimethoxypyridine and 3,5-dimethoxy-2-nitropyridine takes place at the 6 position as expected. For the former compound the rate-acidity profile shows reaction to clearly occur on the conjugate acid, whereas the latter only has a small increase in rate coefficient between H0 — 7.8 and —9.0, suggesting reaction on the free base. Correction of the observed rate coefficients as before gives a rate-acidity profile similar to that of 3,5-dimethoxypyridine showing that the reaction takes place upon the free base of the nitro compound. The corrected... 

By contrast, the rate-acidity profiles for nitration of 3-nitro-4-pyridone, 3-and 5-methyl-2-pyridone and l,5-dimethyl-2-pyridone resemble each other and differ from the above-indicated reaction upon the free base, and correction of the observed rates to allow for the concentration of free base actually present gave rate-acidity profiles of the expected form the corrected entropies of activation then turned out to be positive. Furthermore, if the logarithms of the corrected rate coefficients obtained in media of low acidity were plotted against +log aHlQ, then slopes of near unity were obtained (see above, p. 18), but not otherwise. A similar result was obtained from the nitration data for 4-pyridone in media of low acidity suggesting that here it reacts as the free base. A further test which was applied was to calculate the concentration of nitronium ions in the various media and to correct the observed rate coefficients for this the logarithms of these coeffi-... 

Katritzky et al.509 have also made a kinetic study of the deuteration of substituted pyridine-l-oxides (Table 147). For the 2,4,6-trimethyl compound, the rate-acidity profile shows the conjugate acid to be reacting. The slope of the plot, however, was less (0.33) than that (0.56) obtained for 2,4,6-trimethylpyridine... 

For the 3,5-dimethoxy compound the rate-acidity profile shows the free base to be the reactive species at acidities < -H0 = 3.0 and at higher acidities reaction occurs on the conjugate acid surprisingly, no exchange was detected at the 4 position of this compound. Rates of exchange of the 3-hydroxy compound (at the 2 position) were relatively independent of a wide change in acidity of the medium so that exchange probably occurs on the free base. 

Katritzky et a/.511 have measured rate coefficients for deuteration of 3,5-dimethylphenol and heterocyclic analogues. As in all of the deuteration work of this group, rates of exchange were measured by the nmr method, which is useful for following exchanges at more than one position in the molecule but is, of course, much less accurate than detritiation techniques. In this study, the chemical shift for the ortho and para protons for the parent compound was too small to allow separate integration, but it was apparent that rates of exchange at these two positions did not differ by a factor > 4. From the rate-acidity profile (Table 149) reaction clearly occurs on the neutral species at pD < 3.5 (the log kl versus pD slope was 0.96) and upon the anion at pD > 3.5 (slope zero), and the reactivity of the anion to the neutral molecule was estimated as 107-8, close to the value of 107 noted above. 

In neutral and alkaline media, the rate of exchange at the 3 and 6 position of 4-aminopyridazine is independent of acidity but decreases markedly when the media become more acidic. This was interpreted in terms of a rate-determining removal of the 6-proton by deuteroxide ion to give the ylid (XXIV), which reacts with deuterium oxide in a fast step. A similar result for the 3 and 6 positions of py-ridazin-4-one suggests the same mechanism. For reaction at the 5 position, the rate-acidity profile indicated reaction on the free base as did that for the 5 position of pyridazin-3-one, though the appearance of a maximum in the rate at — HQ = 0.8 was anomalous and suggested incursion of a further mechanism. 

The rate-acidity profile for pyrimidin-2-one indicated reaction on the free base but since the derived second-order rate coefficient is 104 times greater than that for 2-pyridone, and the acidity dependence in the H0 region was also greater, the slope of log kt versus —H0 plot being 0.45, cf. 0.15 for 2-pyridone reaction was, therefore, postulated as occurring via a covalent hydrate, hydration taking place at the 4 position. Methyl substitution increased the rate as expected and N-methyl substitution produced a larger effect than 4,6-dimethyl substitution and this may be due to alteration of the amount of covalent hydration at equilibrium. The data... 

Figure 7.4. Amino acid profiles for seven aliquots from collagen of Burial 8.

C and 5 N values were determined by mass spectrometry (MM 903, VG Isogas), equipped with a CN elemental analyzer (Roboprep CN, Europa Scientific). As control for sample purity, C N ratios from the elemental analyser were compared with C N ratios as calculated from the amino acid profile of the same sample. 

Figure 9.2. Amino acid content (mol %) in collagen extract (dark columns) and serum proteins (light columns) from a skeleton from coastal Peru. Due to a prevalence of degraded and soluble collagen, the nonmineral-bound protein fraction shows a collagen amino acid profile.

Table 17.2a Fatty acid profile of rice bran oil and peanut oil (%)...

Beauchemin et al., 2008) and depend on the level of supplementation, the lipid source and fatty acid profile, and the type of diet. 

The nitrogen content in honey is about 0.04%. Amino acid content accounts for approximately 1% (w/w). Free amino acid profiles have been proposed for the determination of the botanical and geographical... 

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