Peptides: Chemistry and Biology

Diels–Alder Ligation of Peptides and Proteins

“…[16] The application of classical solution-phase synthetic chemistry -where fully protected peptide segments are convergently condensed to form a large polypeptide -showed to be a quite demanding process. Most of the problems rely on the laborious preparation of the fully protected segments and their poor solubility in the coupling reaction medium.…”

“…[16] N-maleoyl-glycine was employed for introduction of the maleimide group in the last step of peptide sequencing. This compound was prepared by reaction of maleimide with methyl chloroformate and N-methylmorpholine in ethyl acetate, followed by conversion of N-methoxycarbonylmaleimide 3 with glycine in basic aqueous medium into Nmaleoylglycine 4 (Scheme 4).…”

A new and efficient protocol for preparation of thiol esters from carboxylic acids and thiols in the presence of 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU)

“…X-Ray crystallographic studies have revealed that TBTU exists, at least in the solid state, as zwitterion 1 comprising a triazol-N-oxide and a guanidinium moiety. 16 N,N'-Diisopropylethylamine (DIPEA) removes the acidic hydrogen from the carboxylic acid, and the carboxylate anion reacts with TBTU. The intermediate acyloxy-aminium/uronium salt 2 cannot be detected and reacts immediately with the benzotriazole derivative to give 3, which reacts with thiol to give the corresponding thiol ester 4 and 1-hydroxybenzotriazole (HOBt, 5) as a water-soluble by-product.…”

Effects of Pro-Arg, a Novel Dipeptide Derived from Protamine Hydrolysate on H2O2-Induced Oxidative Stress in Human Diploid Fibroblasts

“…[7][8] Oligopeptides differ substantially from larger polypeptides (proteins) in their physicochemical and biological properties. The smaller peptides rarely possess strong enough intramolecular attractions to form stable globules.…”