Peptides derivation

FIGURE 5.20 Trypsin is a proteolytic enzyme, or protease, that specifically cleaves only those peptide bonds in which arginine or lysine contributes the carbonyl function. The products of the reaction are a mixture of peptide fragments with C-terminal Arg or Lys residues and a single peptide derived from the polypeptide s C-terminal end. 

Peptides derived from disnlfide-linked protein fragments... 

Lipase M (Mucor javanicus), pH 7, 37°, 70-88% yield. In this case, a- and )3-glycosidic peptide derivatives were deprotected. Acetates on the pyrano-sides were not affected. ... 

The study of the / -thienylalanines and of peptides derived from them as antimetabolites has been continued. - " ... 

Besides sensitive methods for the analysis of proteins, bioinformatics is one of the key components of proteome research. This includes software to monitor and quantify the separation of complex samples, e.g., to analyze 2DE images. Web-based database search engines are available to compare experimentally measured peptide masses or sequence ions of protein digests with theoretical values of peptides derived from protein sequences. Websites for database searching with mass spectrometric data may be found at http //www.expasy.ch/tools, http //prospector.ucsf. edu/ and http //www.matrixscience.com. 

The method illustrated here does have, however, several excellent features.10 The peptide yields are very good even in the synthesis of asparaginyl and glutaminyl peptides, which are ordinarily very difficult to prepare in reasonable yield. Furthermore, the by-products are all water-soluble and, therefore, easily removed from the product peptide derivative. One recrystallization, even under conditions of almost... 

Figure 5.19 MALDI-ToF mass spectrum, providing a molecular-weight profile of the tryptic peptides derived from spot 22 (see Figure 5.18) of the silver-stained two-dimensional gel of the proteins extracted from the yeast S. cerevisiae. From Poutanen, M., Salusjarvi, L., Ruohonen, L., Penttila, M. and KaUddnen, N., Rapid Commun. Mass Spectrom., 15, 1685-1692, copyright 2001. John Wiley Sons Limited. Reproduced with permission.

Gripon P, Cannie I, Urban S (2005). EfScient inhibition of hepatitis B virus infection by acylated peptides derived from the large viral surface protein. J Virol 79 1613-1622 Harris RS, Liddament MT (2004) Retroviral restriction by APOBEC proteins. Nat Rev Immunol 4 868-877... 

The magaiitins are a class of hnear, cationic, faciaUy amphipathic and hehcal antibacterial peptides derived from frog skin [51]. The magaiitins exhibit highly selective and potent antimicrobial activity against a broad spectrum of organisms [52, 53]. As these peptides are faciaUy amphipathic, the magainins have a cationic heli-... 

Lyim and co-workers carried out smdies of the Ap(io 35) peptide - derived from residues 10-35 of the p-amyloid responsible for Alzheimer s disease - which forms fibrils composed of parallel p-sheets [62]. The peptide was compared to its C-terminal PEG-derivatised analogue. TEM experiments showed that both formed fibrils [63] (Fig. 21) but the uranyl acetate stain was not found inside the peptide-PEG fibrils, indicating that PEG was at the outer edge of the fibril. 

A new chapter on amino acids and peptides, which emphasizes the manner in which the properties of biologic peptides derive from the individual amino acids of which they are comprised. 

Cytolytic peptides derived from 16 species of anemones currently comprise this group (Table I). It is likely that as additional species are examin in the future... 

TAKAHASHI M, MORIGUCHI S, IKENO M, KONO S, OHATA K., USUI H, KURAHASHI K, SASAKI R, YOSHIKAWA M (1996) Studies on the Ueum-contracting mechanisms and identification as a complement C3a receptor agonist of oryzatensin, a bioactive peptide derived from rice albumin. Peptides. 17 5-12. 

The first etCCR application has been reported for a partially C— N-labeled phosphotyrosine peptide derived from interleukin-4 receptor ligated to STAT-6 [107] and subsequent studies involve nucleotide cofactors ligated to human recombinant deoxycytidine kinase [108] and epothilone A bound to tubulin [109]. Since etCCR usually involves isotope-labeling schemes for the ligand, its applicability is limited to specific molecular classes. 

Heegard, N. H. H. and Robey, R A., Use of capillary zone electrophoresis to evaluate the binding of anionic carbohydrates to synthetic peptides derived from human serum amyloid P component, Anal. Chem., 64, 2479, 1992. 

Ye J, Kohli LL, Stone MJ. Characterization of binding between the chemokine eotaxin and peptides derived from the chemokine receptor CCR3. J Biol Chem 2000 275 27250-7. 

A group of peptide derivatives such as peptide arginals and boronic acid peptide derivatives belong to another class of reversible thrombin inhibitors. One such inhibitor is PPACK (D-Phe-Pro-Arg chloromethyl ketone), which functions as a powerful irreversible thrombin inhibitor by alkylating the histidine residue at the catalytic site of thrombin (58). It, however, is unstable in neutral solution, as it undergoes cyclization and inactivation. However, the D-methyl derivative of D-Phe-Pro-Arg-H (D-Mephe-Pro-Arg-H) called efegatran, with a molecular mass of 515 Da, is a stable selective reversible inhibitor of thrombin with a K. of approximately 100 nM. The basic amino terminus in this compound is responsible for promoting the specificity toward thrombin (63). 

Henschen A, Lottspeich F, Brand F, Teschemacher H. Novel opioid peptides derived from casein (fi-casomorphins). Hoppe-Seyler s Z. Physiol Chem 1979 360 1217-1224. 

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