Peptides active

Bacitracin. Bacitracin, a cycHc peptide active against gram-positive bacteria, was discovered in 1943. Bacitracin received dmg certification in 1949 (60—62). Whereas human usage of bacitracin is almost exclusively topical, the vast majority of bacitracin manufactured worldwide is used as an animal feed additive. Reviews of work on bacitracin include its chemistry (63—67), comprehensive aspects (62), medical aspects (62,68), biosynthesis on large enzyme complexes and genetics (69—71), and production (71,72). 

Fig. 3.17 Activation of gene transcription by artificial transcription factors. (Top) The artificial activator is composed of three separate functional domains. The DNA binding domain consists of the pyrrole/imidazole polyamides (shown as connected arrows). A tethered linker domain (shown as a coil) connects the DNA binding domain to the peptide activation domain (AD, shown as an oval).

Lavrador K, Murphy B, Saunders J, Struthers S, Wang X, Williams J. A screening library for peptide activated G-protein coupled receptors. 1. The test set. J Med Ghent 2004 47 6864-74. 

In the periphery, some of the primary triggers for these processes have been identified. Acetylcholine seems to be one such factor because stimulation of preganglionic nerves in vivo increases enzyme activity. However, nicotinic and muscarinic receptor antagonists do not completely prevent this increase. The residual activation is attributed to peptides of the secretin-glucagon subgroup, including VIP and secretin both these peptides activate cAMP synthesis. Purinergic transmitters could also be involved. 

Tyndall, J.D., Pfeiffer, B., Abbenante, G. and Fairlie, D.P. (2005) Over one hundred peptide-activated G protein-coupled receptors recognize ligands with... 

M Goodman, KC Stueben. Amino acid active esters. III. Base-catalyzed racemization of peptide active esters. J Org Chem 27, 3409, 1962. 

W Konig, R Geiger. A new method for the synthesis of peptides activation of the carboxyl group with dicyclohexylcarbodiimide and 1-hydroxybenzotriazoles. Chem Ber 103, 788, 1970. 

J Kovacs, R Cover, G Jham, Y Hsieh, T Kalas. Application of the additivity principle for prediction of rate constants in peptide chemistry. Further studies on the problem of racemization of peptide active esters, in R Walter, J Meienhofer, eds. Peptides Chemistry, Structure and Biology. Ann Arbor, MI, 1975, pp 317-324. 

LM Siemens, FW Rottnek, LS Trzupek. Selective catalysis of ester aminolysis. An approach to peptide active esters, (phenylthiomethyl esters). J Org Chem 55, 3507,... 

FIGURE 8.20 Peptides activated at an IV-methylamino-acid residue are postulated to epimer-ize because of the formation of the oxazolonium ion. Evidence for the latter resides in spectroscopic studies,96 and the isolation of a substituted pyrrole that was formed when methyl propiolate was added to a solution of Z-Ala-MeLeu-OH in tetrahydrofuran 10 minutes after dicyclohexylcarbodiimide had been added.95 The acetylenic compound effected a 1,3-dipolar cycloaddition reaction (B), with release of carbon dioxide, with the zwitter-ion that was generated (A) by loss of a proton by the oxazolonium ion. 

J Kovacs. Racemization and coupling rates of N -protected amino acids and peptide active esters predictive potential, in The Peptides Analysis, Synthesis, Biology, Vol. 2, pp 485-539. Academic Press, New York, 1979. 

As host defense peptides are membrane-active molecules, safety mechanisms must be employed to avoid deleterious contacts with host cells. These mechanisms may involve the limitation of peptide activation to specific environments or niche-specific amplification. That most ct-helical peptides remain unstructured in aqueous solution and undergo conformational transitions to an activated state within hydrophobic environments supports this postulate. It has also been postulated that the order of anionic phospholipids in microbial plasma membranes likely induces optimal periodicity of polar residues within host defense peptides at the membrane surface. ... 

The previous examples highlight some of the present technologies being applied for construction of host defense peptides with increased stability and retention of natural peptide activity. Similarly, the examination of host defense peptide candidates has also focused on the identification of methodologies that increase the cost effectiveness of present screening techniques and are also able to examine peptides in a high-throughput fashion. 

The first successful synthesis of a biologically active cyclic peptide, gramicidin S, was accomplished by Schwyzer and Sieber[6,7l via the 4-nitrophenyl ester. The fact that -protected peptide esters can be deprotected to give the peptide active ester salts has made this approach popular not only in the synthesis of sequential polypeptides but also of cyclic peptides. Among the various active esters examined for this purpose, the pentafluorophenyl esters have emerged as the most reactive ones, although a high risk of epimerization is encountered when C-terminal chiral amino acids are involved. 

The polymyxins are a group of basic peptides active against gram-negative bacteria and include polymyxin and polymyxin E (colistin). Polymyxins act like cationic detergents. They attach to and disrupt bacterial cell membranes. They also bind and inactivate endotoxin. Gram-positive organisms, proteus, and neisseria are resistant. 

Marine resources Amino acid sequence/major amino acid in bioactive peptide Activity Reference... 

Structure-activity data on the effects of flatworm FaRPs on 5. mansoni muscle fibres reveal that the replacement of any residue in the YIRFamide signature with the amino acid alanine abolished peptide activity (Day et al., 1997). Although no trematode FaRP has been structurally characterized, evidence from physiology studies reveals that the YIRFamide-containing peptides induce contraction of dispersed 5. mansoni muscle fibres with high... 

Ernst, S., Lange. C., Wilbers, A., Goebeler, V., Gerke, V., and U. Rescher, 2004, An annexin 1 N-terminal peptide activates leukocytes by triggering different members of die formyl peptide receptor family. J Immunol. 172(12) 7669-76. 

Protein name pl MW Full length Signal peptide Activation peptide Mature protein Cysteines Substrate specificity5... 

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