Allylic protection of thiols and cysteine: I: The allyloxycarbonylaminomethyl group
S-allyloxycarbonylaminomethyl derivatives of thiols in general and cysteine in particular are readily deprotected by palladium catalysed hydrostannolysis with tributyltin hydride in the presence of acetic acid. They are perfectly stable in the basic conditions (piperidine/DMF) of Fmoc group removal but tend to decompose, albeit slowly, in the acidic conditions (TFA/CH2Cl2) of t-Bu and Boc groups removal.
Kimbonguila, Andre Malanda,Merzouk, Ahmed,Guibe, Francois,Loffet, Albert
Discrimination of Peptides by Using a Molecularly Imprinted Piezoelectric Biosensor
Based on the direct formation of a molecularly imprinted polymer on gold electrodes, we have developed a peptide sensor for the detection of low-molecular-weight peptides. A new cross-linking monomer, (N-Acr-L-Cys-NHBn)2, was employed to attach the surface of the chip and to copolymerize with other monomers. Interestingly, N-benzylacrylamide participates in the polymerization and recognition is carried out in an aqueous environment. By using quartz crystal microbalance detection, short peptides can be monitored by their interaction with plastic antibodies specific for the target peptides. The selectivity of molecularly imprinted polymers and the sensitivity of such artificial biosensors have been combined to differentiate between traces of oxytocin and vasopressin to the ngmL-1 scale.