L -Lysine

2 H909P9lyQ]ers of carbobenzGxy-L-lysine. We have studied homopolymers of carbobenzoxy-L-lysine with an average degree of polymerization between 50 and 500. They exhibit in dioxane solution different structures as it has already been reported for other solvents M1  

For dioxane concentrations between 55 and 70 X-ray patterns are characteristic of a cholesteric structure. 

For dioxane concentrations between 40 and 55 % and for dry copolymers X-ray patterns exhibit reflexions characteristic of an hexagonal structure [Bragg spacings in the ratio 1, / , /7, 

For dioxane concentrations between 9 and 23 % X-ray patterns exhibit a set of reflexions which can be indexed in a quadratic lattice [Bragg spacings in the ratio 1, /2, /4, /s, /s..]. At both ends of the domain of stability of the quadratic structure one observes a small domain of concentration where a demixion between quadratic and hexagonal structures exists. 

For dioxane concentrations between 25 and 40 %, if the samples are prepared in standard conditions. X-ray patterns exhibit a diffuse band which does not allow the determination of the parameter of the bidimensional lattice nevertheless Infrared spectroscopy reveals the existence of helices. 

Unnatural, optically active amino acids containing the N-vinylpyrrole moiety have been synthesized by condensation of N-vinylpyrrole-2-carbaldehydes with L-lysine (up to 90% yields, Schanes 2.151 and 2.152, Table 2.15) [607]. 

SCHEME 2.151 Selective reactions of N-vinylpyrrole-2-carbaldehydes with L-lysine. 

SCHEME 2.152 Selective reaction of N-vinyl-4,5-dihydrobenz[ ]indole-2-carbaldehyde with L-lysine. 

A rare combination of pharmacophoric N-vinylpyrrole and indispensable amino acid moieties makes this novel class of amino acids important building blocks for drug design. Moreover, the presence of highly reactive N-vinyl group in molecules of the amino acids synthesized fundamentally extends their prospects in the aforementioned applications. 

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Not many fine chemicals have a production value exceeding 10 million per year. Less than a do2en achieve production volumes above 10,000 metric tons per year and sales of > 100 million per year. Apart from the pharmaceutical and pesticide fine chemicals these comprise the amino acids (qv), L-lysine and n,T-methionine used as feed additives (see Feeds AND FEED ADDITIVES), and vitamins ascorbic acid and nicotinic acid. 

The available free carboxyl groups of the DAS—HMS can be linked via a peptide bond to available primary amine groups onto highly antigenic carriers using a carbodiimide (19). The carriers used in this case were bovine semm albumin (BSA) and poly-L-lysine (molecular weight 150,000 to 300,000). The... 

Decarboxylation. Decarboxylation of linear and aromatic carboxyUc acids and of amino acids is common and of practical interest. L-Lysine [56-87-1] (48) can be synthesized by stereospecific decarboxylation of meso- (but not DL-) aa -diaminopimehc acid [2577-62-0] (49). The reaction is catalyzed by Bacillus sphaericus and proceeds in quantitative yields (92). 

After recovery of L-lysine, the residual dl-(49) is epimerized to a mixture of the DL and meso isomers, and the latter is subjected to the same decarboxylation step. This reaction is a part of a microbial process in which glucose is fermented by a lysine auxotroph of E. coli to meso- which accumulates in the medium. Meso-(49) is quantitatively decarboxylated to L-lysine by cell suspensions oi erobacteraerogenes (93). However, L-lysine and some... 

Another biomedical appHcation of mictocapsules is the encapsulation of Hve mammalian ceUs for transplantation into humans. The purpose of encapsulation is to protect the transplanted ceUs or organisms from rejection by the host. The capsule sheU must prevent entrance of harmful agents into the capsule, aUow free transport of nutrients necessary for ceU functioning into the capsule, and aUow desirable ceUular products to freely escape from the capsule. This type of encapsulation has been carried out with a number of different types of Hve ceUs, but studies with encapsulated pancreatic islets or islets of Langerhans ate most common. The alginate—poly(L-lysine) encapsulation process originally developed in 1981 (54) catalyzed much of the ceU encapsulation work carried out since. A discussion of the obstacles to the appHcation of microencapsulation in islet transplantation reviewed much of the mote recent work done in this area (55). Animal ceU encapsulation has also been researched (56). 

L-lysine (N-acetyl-L-lysine) Brevibacterium ketoglutamicum Nocardia sp. hom 75... 

Many kinds of amino acids (eg, L-lysine, L-omithine, t-phenylalanine, L-threonine, L-tyrosine, L-valine) are accumulated by auxotrophic mutant strains (which are altered to require some growth factors such as vitamins and amino acids) (Table 6, Primary mutation) (22). In these mutants, the formation of regulatory effector(s) on the amino acid biosynthesis is genetically blocked and the concentration of the effector(s) is kept low enough to release the regulation and iaduce the overproduction of the corresponding amino acid and its accumulation outside the cells (22). 

L-lysine DL-a-aminocaprolactum hydrolase + Racemase Jichromobactor obae ... 

In Industrial Chemicals. Recendy, as some amino acids (eg, L-glutamic acid, L-lysine, glycine, DL-alanine, DL-methionine) have become less expensive chemical materials, they have been employed in various appHcation fields. Poly(amino acid)s are attracting attention as biodegradable polymers in connection with environmental protection (236). 

Caprolactam is an amide and, therefore, undergoes the reactions of this class of compounds. It can be hydrolyzed, Ai-alkylated, O-alkylated, nitrosated, halogenated, and subjected to many other reactions (3). Caprolactam is readily converted to high molecular weight, linear nylon-6 polymers. Through a complex series of reactions, caprolactam can be converted to the biologically and nutritionally essential amino acid L-lysine (10) (see Amino acids). 

Hydroxy-L-lysine monohydrochloride [32685-69-1 ] M 198.7, [oi]q +17.8° (6M HCl), pKj 8.85, pK 9.83. Likely impurities are 5-a//o-hydroxy-(D and L)-lysine, histidine, lysine, ornithine. Crystd from water by adding 2-9 volumes of EtOH stepwise. 

L-Lysine monohydrochloride [657-27-2] M 182.7, [a] as above. Likely impurities are arginine, D-lysine, 2,6-diaminoheptanedioic acid and glutamic acid. Crystd from water at pH 4-6 by adding 4 volumes of EtOH. Above 60% relative humidity it forms a dihydrate. 

Definitive identification of lysine as the modified active-site residue has come from radioisotope-labeling studies. NaBH4 reduction of the aldolase Schiff base intermediate formed from C-labeled dihydroxyacetone-P yields an enzyme covalently labeled with C. Acid hydrolysis of the inactivated enzyme liberates a novel C-labeled amino acid, N -dihydroxypropyl-L-lysine. This is the product anticipated from reduction of the Schiff base formed between a lysine residue and the C-labeled dihydroxy-acetone-P. (The phosphate group is lost during acid hydrolysis of the inactivated enzyme.) The use of C labeling in a case such as this facilitates the separation and identification of the telltale amino acid. 

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