Lysine chemical structure

The chemical structure of 2,5-hexanedione suggested that it could react with lysine side-chain amino groups in proteins to form pyrroles (see Figure 2-7). In vitro experiments showed that this was, in fact, the case, and that the modified proteins can undergo secondary reactions to yield oxidized and polymeric products (DeCaprio et al. 1982 Graham et al. 1982). Oral administration of 2,5-hexanedione produced evidence that this process can take place in vivo as demonstrated by the detection of 2,5-dimethylpyrrole adducts in serum and axonal cytoskeletal proteins (DeCaprio and O Neill 1985). When a series of... 

The many (possibly more than 30) types of collagens found in human connective tissues have substantially the same chemical structure consisting mainly of glycine with smaller amounts of proline and some lysine and alanine. In addition, there are two unusual amino acids, hydroxyproline and hydroxylysine, neither of which has a corresponding base-triplet or codon within the genetic code. There is therefore, extensive post-translational modification of the protein by hydroxylation and also by glycosylation reactions. 

Several 0-aminoacyl sugars were prepared to study a relationship between taste and chemical structure. Methyl a-D-glucopyranoside, methyl a-D-galactopyranoside and methyl a-D-mannopyranoside were selected as sugar skeletons. As basic amino acids, esters of lysine, ornithine, a,Y-diaminobutyric acid, and a,p-diaminopropionic acid were introduced into 2-0-, 3-0-, and 4-0- positions of sugars leaving only 6-hydroxyl group free. The results of sensory analysis are list in Table VI. O-... 

Scheme4 Chemical structures of poly(Ne-p-phenylazobenzoyl-L-lysine) (V), poly(Ne-p-phenylazobenzenesulfonyl-L-lysine) (VI), and Ne-p-phenylazobenzenesulfonyl-L-lysine (VII).

Scheme 5 Chemical structure of azo-modified polypeptide analogs of poly(L-lysine), VIII (n = 1, 2, 3, and 4) and IX.

SchemelO Chemical structure ofthe polypeptide obtained after introducing spiropyran units into the side chains of succinylated poly(L-lysine) (XVII). 70 ...

Nutritional Effects Due to the Blockage of Lysine. The most important Maillard reaction in food proteins occurs with the c-amino group of lysine. Since lysine is an essential amino acid, nutritional consequences can be expected. These depend on the chemical structure of the lysine derivatives formed. 

Fig. 6 Chemical structures of branched copolymers (x and y denote number averages of repeating units) a polyallylamine-gra/t-poly( /-methyl L-glutamate) (PAAx-g-PMLGluy, X = 175, y = 14), b poly(ethylene oxide)- Zoc/c-(branched-poly(ethylene imine)-gra/t-poly(y-benzyl L-glutamate)) (PEOx- -PEIy-g-PBLGlu2(o.4j+i) x = 113, y = 233, z = 0.2-2.9), and c poly(ethylene oxide)-MocA -([G-3]-dendritic poly(L-lysine)-acetal) (PEOx- -[G-3]-PALLys, x = 113, 227)...

Schemes Chemical structures of polystyrene-b-poly(e-benzyloxycarbonyl-L-lysine) (PS-PZLL) and polystyrene-b-poly(y-benzyl-L-glutamate) (PS-PBLG)...

Fig. 1 a-d Chemical structures of linear peptide block copolymers a 1,2-Polybutadiene-block-poly(L-glutamate) (PB-h-PLGlu). b Polybutadiene-Wock-poly(L-lysine) (PB-h-PLLys). c Poly (L-glutamate)-Wock-poly(L-lysine) (PLGlu-h-PLLys). d Poly(methyl methacrylate)-Wock-peptide-Wock-poly(methyl methacrylate) (PMMA-h-peptide-h-PMMA)... 

Fig. 7 a-g Chemical structures of biohybrid homopolymer amphiphiles. a L-Cysteine-grafted polybutadiene, b Glycosylated polybutadiene, c Glycosylated poly(2-oxazoline). d V,V-l)ialkyl chitosan. e Amphiphilic poly(L-lysine). f PEGylated poly(Z-L-lysine). g Lipid-lysine dendron... 

There are many kinds of natural biodegradable polymers. They are classified into three types according to their chemical structures, i.e., polysaccharides, polypeptides/proteins and polynucleotides/nucleic acids. Among them, polysaccharides, such as cellulose, chitin/chitosan, hyaluronic acid and starch, and proteins, such as silk, wool, poly( y-glutamic acid), and poly(e-lysin), are well known and particularly important industrial polymeric materials. 

Figure 95.1 Amiodarone chemical structure. From http // lysine.pharm.utah.edu/netpharm/netpharm 00/gifs/amiodarone. gif Accessed March 13, 2007, with permission.

Fig. 5.3 Chemical structures of nitric oxide synthase inhibitors. Mj-nitro-L-arginine (L-NNA) (a) 5-[2-[(l-iminoethyl)amino]ethyl]-L-homocysteine (GW274150) (b) A-[3-(aminomethyl)benzyl] acetamidine (1,400 W) (c) AG-monomethyl-L-arginine (l-NMMA) (d) 7-nitroindazole (7-NI) (e) aminoguanidine (f) A6-iminoethyl-L-lysine (L-NIL) (g)...

We have shown in the last topic that a triplet code with four letters (DNA/RNA bases) to choose from is mathematically sufficient to encode 20 amino acids, but is it structurally sufficient What is there about a set of three nucleotide bases that enables it to recognise and specify the very different chemical structure of a single amino acid Likewise, how can very similar codons specify very different amino acids. How is it that AUG can specify methionine while, with only one base different in each case, AAG specifies lysine, GUG specifies valine, AUC specifies isoleucine The answer to this puzzle lies, as so often, in the properties of a remarkable set of enzyme proteins and a matching set of RNA molecules called transfer RNA (tRNA), which together provide, in effect, an adaptor kit. 

Ptomaines. Name, derived from modern Greek ptoma=cadaver, for the so-called cadaveric poisons formed from putrefying proteins. The enzymatic decarboxylation products of the amino acids lysine and L-omithine ( cadaverine and putrescine), previously known as R, are, however, relatively non-toxic biogenic amines. Today the name P. is used for the toxic metabolic products of putrefactive bacteria that colonize rotting, protein-containing foodstuffs such as meat, fish, etc. These P. have widely differing chemical structures their activities are purported to be similar to those of the plant toxins such as strychnine, atropine, etc.. 

Chart 5.4 Chemical structures of poly(L-lysine) and poly(L-glutamic acid). 

FIGURE 8.16 Chemical structure of random PEAs having hydrophobic L-phenylalanine imits and different percentages of hydrophiUc L-lysine units. After deprotection, PEAs are provided of functional amine pendant groups. 

FIGURE 8.21 Chemical structure of the copoly(ester amide) based on L-lysine and L-leucine amino adds that has been developed to prepare microspheres for oral insulin delivery. 

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