A new solid-phase disulfide ligation method is developed to prepare a disulfide peptide from two types of Cys-containing peptide fragments with minimum purification steps. In combination with the subsequent intramolecular amide bond formation, a cyclic nonapeptide, oxytocin, was efficiently synthesized as a fundamental model for more complex cyclic peptides.

The lithium corrole complex (Mes(2)(p-OMePh)corrole)Li(3)·6THF (1·6THF), prepared via deprotonation of the free-base corrole with lithium amide, acts as precursor for the preparation of cyclopentadienyl zirconium(iv) corrole (2) and pentamethylcyclopentadienyl titanium(IV) corrole (3).

The widely expressed dipeptidyl peptidase-4 enzyme rapidly cleaves the gut hormone glucagon-like peptide-1 [GLP-1(7-36)amide] at the N terminus to generate GLP-1(9-36)amide. Both intact GLP-1(7-36)amide and GLP-1(9-36)amide exert cardioprotective actions in rodent hearts; however, the mechanisms underlying the actions of GLP-1(9-36)amide remain poorly understood. We used mass spectrometry of co...

GroE, the chaperonin system of Escherichia coli, prevents the aggregation of partially folded or misfolded proteins by complexing them in a form competent for subsequent folding to the native state. We examined the exchange of amide protons of cyclophilin A (CypA) interacting with GroEL, using NMR spectroscopy. We have applied labeling pulses in H2O to the deuterated GroEL-CypA-complex. When AT...

route to vinyl epoxides and vinyl aziridines via chiral sulfur ylides, we were keen to develop their potential in synthesis further. It had been reported that palladium-catalyzed reactions of vinyl epoxides and aziridines with doubly activated Michael acceptors gave tetrahydrofurans and pyrrolidines in good yield but usually with poor stereocontrol. However, related reactions with singly activa...

Raman spectra of native and solubilized feather keratin have been obtained, and the amide I and amide 111 regions have been analyzed by band resolution techniques. The amide I region of the native form indicates that at least 64% of the protein has an antiparallel chain pleated sheet structure, the remainder being unordered. For the solubilized keratin all of the protein is in an unordered stat...

Amide-iminol tautomerism was studied for ionized oxamic acid (OA+•) in the gas phase using theDFT method with the UB3LYP functional and various basis sets {6-31++G(d,p), 6-311+G(d,p), and augcc-pVDZ}. Among twenty tautomers-rotamers possible for OA+•, eleven isomers were found to bethermodynamically stable. Similarly as for the neutral molecule, ionization (OA → OA+• + e) favors theamidization ...

The authors use an environmental friendly, solvent-free method to prepare metal (II) complexes of cloxacillin and determine the activity complexes. are more active against bacteria isolates than free cloxacillin. spectral studies showed (ligand) as monobasic bidentate material that form a complex with ion through carbonyl amide carboxylate groups carboxylic acid, microanalysis results prove lig...

The functionalization of C?H bonds in light alkanes, particularly to form C?N bonds, remains a challenge. We report the dehydrogenative coupling amides with C1–C4 hydrocarbons N-alkyl amide products tBuOOtBu as oxidant, and copper complex phenanthroline-type ligand catalyst. reactions occurred good yields benzene or supercritical carbon dioxide solvents. This strategy allowed for determination ...

BACKGROUND Fourier Transform Infrared Imaging (FTIRI) is used to investigate the amide anisotropies at different surfaces of a three-dimensional cartilage or tendon block. With the change in the polarization state of the incident infrared light, the resulting anisotropic behavior of the tissue structure is described here. METHODS Thin sections (6 mum thick) were obtained from three different ...