Lysine peptide

Repeated addition of MDC to Q11 did occur, but the dominant product was Q11 with a single MDC. The fraction of Qll with higher numbers of attached MDC decreased for increasing MDC number. Separately, a lysine peptide that contained the bioactive RGD [73] sequence ( -dansyl-GLKGGRGDS-Am) was successfully TGase crosslinked with self-assembled Qll five distinct Qll-dansyl RGD were detected by mass spectrometry. 

Synthesis of the D-Lysine Peptide Nucleic Acid Monomer... 

Enantiomerically pure tripeptide aldehydes are typically synthesized by azide or mixed anhydride coupling of dipeptides to a-amino aldehydes or their semicarbazone derivatives. For example, Ac-Leu-Leu-Phe-H was synthesized by the azide coupling of Ac-Leu-Leu-OH with Phe-H semicarbazone, prepared by catalytic hydrogenation of Z-Phe-H semicarbazone. The tripeptide semicarbazone was deprotected with 37% HCHO/HC1 solution (Table 2)J5 C-terminal argininal, ornithinal, and lysinal peptides such as Z-Leu-Leu-Orn(Boc)-H and Z-Leu-Leu-Lys(Boc)-H were prepared by mixed anhydride coupling of Z-Leu-Leu-OH with Orn(Boc)-H semicarbazone or Lys(Boc)-H semicarbazone. 3 Z-Leu-Leu-Arg(N02)-H was prepared by mixed anhydride coupling of Z-Leu-Leu-OH with Arg(N02)-H semicarbazone trifluoroacetate, prepared from the reaction of TFA and Boc-Arg(N02)-H semicarbazone (Table 2) J31... 

As discussed in Section 11.2.2, biotin is incorporated covalently into biotin-dependent enzymes as the e-amino-lysine peptide, biocytin. On catabolism... 

Relatively few natural e-lysine peptides have been reported. Biocytin has been shown to be e-A-biotinyl-n-lysine by degradative and synthetic studies (Peck et al, 1952). 

The suggestion that e-amino lysine peptide linkages occur in collagen is based almost entirely on the evidence of the tripeptide isolated by Mechanic and Levy (1959). The quantity of the tripeptide obtained accounted for only a fraction of a per cent of the lysine present. Their suggestion that 30 or 40 % of the lysine may be bound via its t-amino groups seems most improbable. From the evidence presented above no more than a few per cent of the lysine can be involved in this way. 

Rucker, A.L. and Creamer, T.P. Polyproline II helical structure in protein unfolded states lysine peptides revisited. Protein Sci., 11, 980, 2002. 

In the biotransformation process to BMS-199541-01, yields of65-70 mole-% were achieved without recycling of the L-glutamate resulting from the reduction of a-ketoglutarate yields were substantially lower. L-Lysine E-aminotransferase also catalyzes the oxidation of N-a-protected L-lysines as well as L-lysine peptides such as N-protected L-met-L-lys. 

Competing photodecomposition pathways have been observed in sulpho-namides and sulphonylureas, and the photohydrolysis of sulphonamides, via the formation of donor-acceptor ion pairs with electron-donating aromatic compounds, has been reported.Irradiation of AT-tosylmethylphenethylamine (188) in the presence of veratrol (189) in ethanol, for example, gave methyl-phenethylamine (190) in 66% yield. This procedure has also been employed in the selective detosylation of lysine peptides. 

Irradiation of N-tosylamines in aqueous ethanol in the presence of an aromatic electron donor such as 1,4-dimethoxybenzene, and a reductant such as sodium borohydride induced detosylation and liberation of the corresponding primary or secondary amine 70 selective deprotection of some Ne- tosyl-lysine peptides was successful. 

Chapter 33, the L-lysine peptide of the ring-opened form of diazepam was described. Similarly acylation of the 3-amino group of the pyrrolidine ring in a series of quinolone antibacterial agents yielded interesting compounds (Fig. 36.17). 

Inspect the low-mass region for the ji-ion. To assign the C-terminal amino acid, the low-mass region of the spectrum is inspected to identify the yi-ion at either m/z 147, for C-terminal lysine peptides, or m/z 175 for C-terminal arginine peptides. The m/z of the yi-ion is then used to calculate the m/z of the b i-ion, and the high-mass region of the product ion spectrum is inspected to identify that ion. 

Pirollo et al. developed a nanoimmunoliposome modified with anti-TfR scFV to deliver siRNA to tumor cells. A fluorescein-labeled siRNA was delivered via systemic injection and it was specifically distributed into primary and metastatic tumor cells [110]. Later, the authors developed a similar nanoimmunoliposome for an anti-Her-2 siRNA. To enhance the endosomal release, a pH-sensitive histidine-lysine peptide was included in the complex. The in vitro results showed that the complexes can sensitize human cancer cells to che-motherapeutics. Furthermore, systemic delivery of the siRNA significantly inhibit tumor growth in a pancreatic cancer model [109]. 

Comparison of the complex-formation constants for bofli 1 1 (57 and 58) and 1 2 (such as 59) species ° with those obtained for the respective copper(II) complexes with parent amino acids revealed that the fructosyl moiety provides for an additional chelate effect in D-fructose-a-amino acids and as a consequence, a significant increase in the complex stability. In the absence of an anchoring chelating group, such as a-carboxylate, the D-finctosamine structure is not a good copper(II) chelator, and Cu(n) expectably does not form stable complexes with the carbohydrate in A -d-Iructose-L-lysine peptides. Although it would be expected that iron(III) complexes with D-finctose-amino acids in aqueous solutions, no related thermodynamic equilibrium studies have been done so far for this important redox-active metal. 

Selective coupling can also be used for sequencing COOH-terminal lysine peptides that are contaminated with peptides lacking lysine. The mixture is coupled by the diisothiocyanate method. All peptides become coupled at their NH2-terminal a-amino groups, but the non-lysine peptides become detached after the first cycle of the Edman degradation. 

Mermut, O., Phillips, D.C., York, R.L., McCrea, K.R., Ward, R.S., Somorjai, Ga In situ adsorption studies of a 14-amino acid leucine-lysine peptide onto hydrophobic polystyrene and hydrophilic silica surfaces using quartz crystal microbalance, atomic force microscopy, and sum frequency generation vibrational spectroscopy. J. Am. Chem. Soc. 128, 3598-3607 (2006)... 

Apte, J.S., Gamble, L.J., Casmer, D.G., Campbell, C.T. Kinetics of leucine-lysine peptide adsorption and desorption at -CH3 and -COOH terminated alkylthiolate monolayers. Biointerphases 5, 97-104 (2010)... 

Factor X, fibrin-stabilizing factor the last clotting factor to act in the blood coagulation cascade. It is an a2-plasma globulin of M, 350,000 and contains 2a- and 2P-chains of M, 100,000 and 77,000, respectively. It is activated by thrombin in the presence of Cs to factor Xllla, which catalyses the formation of y-glutamyl-E-lysine peptide bonds in a calcium-dependent transamidation reaction. These bonds serve to cross-link the fibrin chains into a 3-dimensional network, the clot. 

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