Guanidine peptides

The reactivities of analogous aminium and phosphonium derivatives are essentially equivalent. However, aminium-based reagents can, if used inappropriately, cause capping of resin-bound amino groups through formation of N-terminally guanidinated peptides 23 (38). This side-reaction occurs most... 

Edman Degradation of Guanidinated Peptide 1-16 Sequence Leu-Val-Homoarg-Val-... 

Guanidinated Peptide 1-16 Control for Edman Degradation (No Phenylisothiocyanate)... 

Exposito Eernandez-Suarez, M., Iglesias, T., Munoz, L., and Riguera, R. (2001) Total synthesis and absolute configuration of minaleamine A, a guanidine peptide from the marine tunicate Didemnum rodriguesi. J. Org. Chem., 66, 4206 213. 

This Fmoc analog is prepared from the chloroformate, O-succinimide, or p-nitrophenyl carbonate and is cleaved with 10% piperidine in 1 1 6M guanidine/IPA. It was designed to interact strongly on a column of porous graphitized carbon so as to aid in the purification of peptides after cleavage from the resin. 

SnCl4, AcOH, THF, CH2CI2, toluene or CH3CN, 82-98% yield. This method was developed because acid-based methods were incompatible with the presence of a thioamide peptide bond. Guanidines were cleanly deprotected. ... 

Zhong HM, Greco MN, MaryanofF BE. Solid-phase synthesis of arginine-containing peptides by guanidine attachment to a sulfonyl linker. J Org Chem 1997 62 9326-9330. 

Dissolve a disulfide-containing protein or peptide at a concentration of l-10mg/ml in 6M guanidine hydrochloride, 0.01 M sodium phosphate, 0.15 M NaCl, pH 7.4. Alternative... 

Apply to the column 1.0ml of peptide solution (dissolved in equilibration buffer) to be reduced. Normally, small peptides (molecular weight less than or equal to that of insulin) require no deforming agent (denaturant) such as guanidine to be completely reduced. 

Brancia, F.L., Oliver, S.G., and Gaskell, S.J. (2000) Improved matrix-assisted laser desorption/ionization mass spectrometric analysis of tryptic hydrolysates of proteins following guanidination of lysine-containing peptides. Rapid Comm. Mass Spectrom. 14, 2070-2073. 

A second method of incorporating phase into the selection process is to immobilize the target. Essentially an affinity chromatographic method, this allows nonbound library constituents to be washed away, leaving the selected compound(s) bound to resin. Eliseev s guanidine resin and Still s peptide-bearing beads, both discussed above in the context of exchange reactions, are examples of these. 

A library containing several million beads can be screened in a single afternoon. Furthermore, the library is reusable, as it may be washed in 8 M guanidine hydrochloride and then re-screened using a different probe. This split synthesis approach displays the ability to generate peptide libraries of incredible variety, variety that can be further expanded by incorporation of, for example, D-amino acids or rarely occurring amino acids. 

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