A peptide corresponding to the thirty-one amino acid sequence of human proinsulin C-peptide (positions 33–63 of proinsulin) was synthesized by the solid-phase method. The product was purified consecutively by gel filtration, DEAE-cellulose chromatography, and high-performance liquid chromatography (HPLC). The purified material behaved as a single component in reversed-phase HPLC, gave correct amino acid ratios, and was not distinguished from natural human C-peptide in terms of immunoreactivity and chromatographic behaviors. The α→β transpeptidation at the Asp-Leu sequence, possible to occur associated with the HF cleavage, was studied using model peptides to demonstrate that the formation of β-peptide was 3–4% regardless of whether the β-carboxylic acid is free or protected as a benzyl ester.
Functionalization of Sulfonamide-Containing Peptides through Late-Stage Palladium-Catalyzed C(sp<sup>3</sup>)–H Arylation
作者:Qingqing Bai、Jian Tang、Huan Wang
DOI:10.1021/acs.orglett.9b01953
日期:2019.8.2
Bioactive peptides are emerging as promising candidates of clinic therapeutics. Here, we report a method for late-stage functionalization of sulfonamide-containing peptides through Pd-catalyzed C(sp3)–H arylation. In this protocol, the backbones of N-sulfonated peptides act as directing groups, which allows site-specific arylation of benzylsulfonamide moiety. This chemistry exhibits broad substrate
The Steric Hindrance of the Stepwise Reaction of<i>N</i>-Carboxy α-Amino Acid Anhydride with the α-Amino Acid Ester
作者:Masanao Oya、Tomoko Takahashi
DOI:10.1246/bcsj.54.2705
日期:1981.9
The mechanisms of the reactions of 4-alkyloxazolidinediones (1) (N-carboxy α-amino acid anhydrides(NCAs)) with α-amino acid benzyl ester p-toluenesulfonates (2) were investigated in acetonitrile containing triethylamine at low and room temperatures. Two types of reactions were observed: (1) the polymerization of NCAs was initiated with a small amount of 2 to produce polypeptides (6), and (2) the dipeptide
A series of carboxyl-containing N-alkyldipeptides have been found to posess antiviral potency--specifically against herpes simplex virus--by selectively inhibiting the viral ribonucleotide reductase enzyme.