3303-34-2Relevant articles and documents
Highly Productive Continuous Flow Synthesis of Di- and Tripeptides in Water
Jolley, Katherine E.,Nye, William,González Ni?o, Carlos,Kapur, Nikil,Rabion, Alain,Rossen, Kai,Blacker, A. John
, p. 1557 - 1565 (2017/10/25)
The reaction of amino acid derived N-carboxyanhydrides (NCAs) with unprotected amino acids under carefully controlled aqueous continuous flow conditions realized the formation of a range of di- and tripeptide products in 60-85% conversion at productivities of up to 535 g·L-1h-1. This required a fundamental understanding of the physicochemical aspects of the reaction resulting in the design of a custom-made continuous stirred tank reactor (CSTR) with continuous solids addition, high shear mixing, automated pH control to avoid the use of buffer, and efficient heat removal to control the reaction at 1 ± 1 °C.
DIPEPTIDE-CONTAINING COMPOSITION FOR ORAL ADMINISTRATION
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Page/Page column 6, (2008/12/06)
The present invention provides a composition for oral administration, which comprises at least one kind of dipeptide represented by the formula: ????????X-Y (wherein X represents alanyl, glycyl, arginyl, seryl, α-aspartyl or α-glutamyl, and Y represents valine, leucine or isoleucine), with an object of providing a composition for oral administration which is excellent in nutrition, pharmacological effect and gustation and comprises at least one kind selected from valine, leucine and isoleucine, or providing a composition for oral administration which is excellent in processing characteristics such as solubility and tableting property and comprises at least one kind selected from valine, leucine and isoleucine.
Rates of reduction of N-chlorinated peptides by sulfite: Relevance to incomplete dechlorination of wastewaters
Jensen, James S.,Helz, George R.
, p. 516 - 522 (2007/10/03)
Biologically induced fragmentation of proteins during wastewater treatment produces peptides, which form long-lasting organic chloramines when the water is disinfected with Cl2. To protect aquatic wildlife from residual chlorine, including chloramines, wastewaters are often treated with sulfur dioxide or sulfite salts. This strategy incompletely eliminates residual chlorine species. Here we report that dechlorination rate constants of N- chloropeptides are 1-2 orders of magnitude smaller than those for NH2Cl and some aliphatic organic chloramines. Slow rates explain the prevalence of N- chloropeptides in dechlorinated wastewaters after faster reacting chlorine species have been eliminated. Dechlorination is subject to general acid catalysis. For N-chlorinated leucylalanine, the rate law above pH 6 in phosphate buffer at 25 °C and / ? 0.1 M is as follows: rate = (9.92 ± 0.41 x 103[H2PO4-] + 5.70 ± 0.52 x 108[H3O+] + 5.3 ± 0.2)[SO32-][Cl- Leu-Ala] (concentrations in M, time in s). Rate constants for other peptides appear to be of similar magnitude; variations in the acid-catalyzed terms among different hydrophobic peptides correlate with solvation energies of side chains. The kinetic data suggest that reducing N-chloropeptides in wastewaters by 75% or more will require reaction times generally >0.5 h at environmentally acceptable S(IV) doses and pH values. Biologically induced fragmentation of proteins during wastewater treatment produces peptides, which form long-lasting organic chloramines when the water is disinfected with Cl2. To protect aquatic wildlife from residual chlorine, including chloramines, wastewaters are often treated with sulfur dioxide or sulfite salts. This strategy incompletely eliminates residual chlorine species. Here we report that dechlorination rate constants of N-chloropeptides are 1-2 orders of magnitude smaller than those for NH2Cl and some aliphatic organic chloramines. Slow rates explain the prevalence of N-chloropeptides in dechlorinated wastewaters after faster reacting chlorine species have been eliminated. Dechlorination is subject to general acid catalysis. For N-chlorinated leucylalanine, the rate law above pH 6 in phosphate buffer at 25 °C and I≈0.1 M is as follows: rate = (9.92±0.41×103[H2 PO4- ]+5.70±0.52×108[ H3O+]+5.3±0.2) [SO32-][Cl-Leu-Ala] (concentrations in M, time in s). Rate constants for other peptides appear to be of similar magnitude; variations in the acid-catalyzed terms among different hydrophobic peptides correlate with solvation energies of side chains. The kinetic data suggest that reducing N-chloropeptides in wastewaters by 75% or more will require reaction times generally >0.5 h at environmentally acceptable SIV doses and pH values.