Amino acid solution

The dielectric constants of amino acid solutions are very high. Thek ionic dipolar structures confer special vibrational spectra (Raman, k), as well as characteristic properties (specific volumes, specific heats, electrostriction) (34). 

AM I NO ACIDS A microscopic filter is attached to the IV line when amino acid solutions are administered. The filter prevents microscopic aggregates (particles that may form in the IV bag) from entering the bloodstream where they could cause massive emboli. 

Crystalline amino acid bulk solutions are supplied by various manufacturers in various concentrations (e.g., 3.5%, 5%, 7%, 8.5%, 10%, 15%, and 20%). Different formulations are tailored for specific age groups (e.g., adults and infants) and disease states (e.g., renal and liver disease). Specialized formulations for patients with renal failure contain higher proportions of essential amino acids. Formulas for patients with hepatic encephalopathy contain higher amounts of branched-chain and lower amounts of aromatic amino acids. However, these specialized formulations should not be used routinely in clinical practice because their efficacy has not been clearly demonstrated. Crystalline amino acid solutions have an acidic pH (pH = 5-7) and may contain inherent electrolytes (e.g., sodium, potassium, acetate, and phosphate). 

Amino acids Amino acids goal of -110 g/day 440 kcal/day (should provide -1 0-20% of total daily calories) If using a 10% stock amino acid solution 110 g x 100 mL 11 oo mL of 10% stock solution 10g... 

Hydrogen sulfide formation has been demonstrated in pediatric intravenous amino acid solutions used to treat infants with high protein requirements (Decsi and Koletzko 1993). Levels up to 1.96 ppm were found, presumably formed by sulfide liberation from cysteine derivatives during heat sterilization. 

Decsi T, Koletzko B. 1993. Hydrogen sulfide in pediatric parenteral amino acid solutions. JPediatr Gastroenterol Nutr 17 421-423. 

Socha P, Heim P, Koletzko B. 1996. Short report—hydrogen sulfide in parenteral amino-acid solutions. Clinical Nutrition 15 34-35. 

The processes occurring at hydrothermal systems in prebiotic periods were without doubt highly complex, as was the chemistry of such systems this is due to the different gradients, for example, of pH or temperature, present near hydrothermal vents. Studies of the behaviour of amino acids under simulated hydrothermal conditions showed that d- and L-alanine molecules were racemised at different rates the process was clearly concentration-dependent. L-Alanine showed a low enantiomeric excess (ee) over D-alanine at increasing alanine concentrations. The same effect was observed with metal ions such as Zn2+ in the amino acid solution. Thus, homochi-ral enrichment of biomolecules in the primeval ocean could have resulted under the conditions present in hydrothermal systems (Nemoto et al., 2005). 

Many compounds are less soluble as racemates than as their pure enantiomers. It thus appears probable that evaporation of an amino acid solution with a low ee should cause selective precipitation of the racemate crystals, which in turn should lead to an increase of the ee. Extremely simple manipulations, carried out in the chemistry department of Columbia University, led to a drastic increase in enantiomeric excess of phenylalanine 500 mg phenylalanine (with a 1 % ee of the L-component) was dissolved in water, and the resulting solution slowly evaporated until about 400 mg had crystallised out. The remaining solution contained a few mg of phenylalanine with 40% ee of the L-component (i.e., a 70 30 ratio of l to d). If 500 mg of such a solution (40% ee in water) is allowed to evaporate and is separated from the racemate, the result is about 100 mg, with 90% ee of the L-enantiomer (Breslow and Levine, 2006). 

Square pieces (0.5 cm x 0.5 cm) of Whatmann 3MM paper are preblocked with 50 /d of 50 X MEM amino acid solution (Invitrogen) and dried under an Infra-Rediator lamp (Fisher). Whatmann squares are labeled with a pencil, 5 /d of cell lysate is spotted onto each square, and the filter is dried. 

Figure 7.5 The Edman degradation method, by which the sequence of a peptide/polypeptide may be elucidated. The peptide is incubated with phenylisothiocyanate, which reacts specifically with the N-terminal amino acid of the peptide. Addition of 6 mol l-1 HCl results in liberation of a phenylthiohydantoin-amino acid derivative and a shorter peptide, as shown. The phenylthiohydantoin derivative can then be isolated and its constituent amino acid identified by comparison to phenylthiohydantoin derivatives of standard amino acid solutions. The shorter peptide is then subjected to a second round of treatment, such that its new amino terminus may be identified. This procedure is repeated until the entire amino acid sequence of the peptide has been established...

Modified amino acid solutions are designed for patients with altered protein requirements associated with hepatic encephalopathy, renal failure, and metabolic stress or trauma. However, these solutions are expensive and their role in disease-specific PN regimens is controversial. 

Infants treated before 1979 received protein hydrolysates containing high concentrations of phosphate which limited the concentration of calcium that could be used without causing precipitation. Beginning in 1979 crystalline amino acid solutions which contained less obligatory phosphate became available these allowed greater latitude in the concentrations of calcium and phosphate that could be achieved. The data in Table I suggest that the severity of demineralization and the incidence of fractures and rickets will decrease if more calcium is added to the parenteral alimentation solution. 

Calculate caloriemitrogen ratio of a TPN solution consisting of 500 mL of 50% dextrose and 500 mL of 8.5% amino acid solution. 

A TPN solution contains 0.5 L of 25% dextrose and 0.5 L of 8.5% amino acid solution. What is the non-nitrogen calories to grams of nitrogen ratio (Cal N) for this TPN formula ... 

Using separate capillary tubes for each standard and sample, spot the paper by placing a small drop of each from the capillary tube at the appropriate points (where the lines cross). The smaller the spot the better. Perform this step carefully. Allow the spots to dry. Sample solutions should be spotted a second time over the original spot to make certain that there is sufficient amino acid in each spot. A single spotting is adequate for the four amino acid solutions. 

To cuvette (BLANK) add 0.1 ml distilled water and note absorbance / ,. To the other cuvette (TEST) add 0.1 ml amino acid solution and again record absorbance T. ... 

Note - Some products such as amino acid solutions and multiple electrolyte solutions containing dextrose will not be brought to near physiologic pH by the addition of sodium bicarbonate neutralizing additive solution. This is due to the relatively high buffer capacity of these fluids. 

Repool beads tind redistribute them into amino acid solutions... 

Standard adult TPN formula, Baxter Standard adult amino acid solution, Fresenius... 

Popinska, K., Kierkus, I, Lyszkowska, M., Socha, I, Pietraszek, E., Kmiotek, W., and Ksiazky, J. (1999), Aluminum contamination of parenteral nutrition additives, amino acid solutions, and lipid emulsions, Nutrition, 15, 683-686. 

Unlabeled amino acid solution (10 x stock) See Table 3.2.6. These amino acids, which are included in the natural L-amino acid kit (ICN Biomedical, 100586), except for the two alkaline amino acids (cystine and tyrosine), are mixed into a 100-ml volumetric flask. Then, 10 ml of L-glutamine (200 mM, Sigma G7513 must be in solution before use) and 50 ml water are added and the solution stirred until all components are dissolved. For L-cystine and L-tyrosine, the indicated amount is added to a 10-ml volumetric flask and the pH adjusted to > 8.0 by adding 2N NaOH drop by drop until the amino acids are dissolved. Then water is added to the 10-ml mark and the solution transferred to a 100-ml flask to complete the solution. Aliquots of 10 ml are prepared using 15-ml conical screw-top tubes and stored at -80°C. 

Table 3.2.6 Unlabeled amino acid solution (10 x stock)...

Arakawa T, Timasheff SN. Preferential interactions of proteins with solvent components in aqueous amino acid solutions. Arch Biochem Biophys 1983 24(1) 169-177. 

The mutagenic activities of the chlorinated humic acid and amino acid solutions are of the same order of magnitude as that observed in treated water. (The low numbers of revertants at the higher dose levels indicate toxicity). Therefore, these compounds may be precursors of the mutagenicity that is observed in XAD-2/ethyl ether extracts of treated water and that is the direct result of chlorination in drinking water treatment. 

M) 15 min. only for a model amino acid solution microwave heating... 

Dabsyl Chloride (4-dimethyl-aminoazobenzene-4-sulfonyl chloride) Aabs = 420 nm. Derivatives are very stable (days) and can be formed from both primary and secondary amino acids. Detection is by absorption only. Detection limits are in the high picomole range. Reaction time is typically around 10 minutes at 70°C. Completeness of reaction can be adversely affected by the presence of high levels of various salts. Because reaction efficiency is highly matrix dependent and variable for different amino acids, standard amino acid solution should be derivatized under similar conditions/matrix for accurate calibration. Commercial systems available uti-... 

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