Amino acids methods

Amino acid Method Japan World Ptice, /kg... 

Simply on the basis of the normal composition of marine organisms, we would expect proteins and peptides to be normal constituents of the dissolved organic carbon in seawater. While free amino acids might be expected as products of enzymic hydrolysis of proteins, the rapid uptake of these compounds by bacteria would lead us to expect that free amino acids would normally constitute a minor part of the dissolved organic pool. This is precisely what we do find the concentration of free amino acids seldom exceeds 150 xg/l in the open ocean. It would be expected that the concentration of combined amino acids would be many times as great. There have been relatively few measurements of proteins and peptides, and most of the measurements were obtained by measuring the free amino acids before and after a hydrolysis step. Representative methods of this type have been described [245-259]. Since these methods are basically free amino acid methods, they will be discussed next in conjunction with those methods. 

With these newer methods of protein separation and amino acid analysis he prepared serum protein fractions by serial salting out with ammonium sulfate and by the Sober and Peterson DEAE cellulose columns (42), using the sera of reptile, fowl, and mammalian blood. Some of the amino acid analyses were carried out by the automatic amino acid methods of Hirs, Moore, and Stein (18). Fortified with this plethora of data, Block now had the opportunity to re-examine not only the ratio of the basic amino acids, but at least 12 amino acids in a variety of protein fractions prepared by at least two different procedures. With the aid of a statistician he determined the significance of the constancy of the molar ratios of pairs of amino acids and found that in spite of the marked variation of the absolute amounts of an amino acid, the molar ratios of certain pairs remain relatively constant among the numerous protein components of animal sera. 

Eyre, D. Collagen cross-linking amino acids. Methods. Enzymol. 1987 144 115-139. 

Chiral cychc and acyclic allylsulfoxonium ylides are generated from sulfoxonium-substi-tuted y,8-unsaturated a-amino acids (method A) and 1-alkenylsulfoxonium salts (method B) upon treatment with DBU (1) [51] (Scheme 3.31). Their apphcation to the asymmetric aziridination of A-ferf-butylsulfonyl imine ester, generated either in situ (method A) or externally added (method B), affords the corresponding alkenylaziridinecarboxylate with medium to high diastereoselectivity and enantioselectivity. 

Amino acid Method of manufacture Annual tonnage (1987)... 

Typical procedures. AOC- and MPC-amino acids. Method A [379] Amyl chloro-formate Dried phosgene (105 g, 1.06 mol) (for a phosgene source, see Chapter 7) was introduced into a solution of t-amyl alcohol (46 g, 0.52 mol) in dry diethyl ether (500 mL), and then the mixture was cooled to 60 °C in an acetone/dry-ice bath. A solution of pyridine (41 g, 0.52 mol) in dry diethyl ether (500 mL) was added dropwise to the cooled mixture with vigorous stirring. Then the reaction mixture was stored overnight in a deep freezer at —20 °C. The formed pyridine hydrochloride was removed by filtration, and the mother liquor was concentrated to a small volume (about 120 mL) in an ice/water bath under reduced pressure. The product thus obtained was used without further purification in the following reactions. Its purity was determined by acylating a known amount of phenylalanine methyl ester as described below it was found that about 4 mL of the product corresponded to 0.01 mol. The yield was about 60%. 

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