Although intensively studied, the high-resolution crystal structure of the peptide DFNKF, the core-segment of human calcitonin, has never been described. Here we report how the use of iodination as a strategy to promote crystallisation and facilitate phase determination, allowed us to solve, for the first time, the single-crystal X-ray structure of a DFNKF derivative. Computational studies sugg...

Direct iodination of benzothiazoles under strong oxidative/acidic conditions leads to a mixture iodinated heteroarenes with 1–2 major components, which are easily separable and structures depend on the I2 equivalents used. Among unexpected but dominant products were identified 4,7-diiodobenzothiazoles rare substitution pattern for SEAr reactions this scaffold. These employed in synthesis 4,7-bi...

The crystal structure of the title compound, C(27)H(45)N(3), has been determined as part of our investigation into the hydro-phobic modification of amino-glycoside anti-biotics. The isopropyl group showed disorder for the tertiary carbon (equal occupancies), with high thermal motion for the peripheral atoms of the isopropyl and azide groups also apparent in the structure. The axial disposition ...

An arylazido ubiquinone derivative, 2,tdimethoxy5-methyl-6{10-[4-(azid0-2-nitroanilinopropionoxy)]decyl} -1,4-benzoquinone, restores about 60% of the electron transfer activity to ubiquinoneand phospholipid-depleted succinateor ubiquinol-cytochrome c reductases, compared to that restored by 2,3-dimethoxy5-methyl-6-(1O-bromodecyl)-1,4-benzoquinone. The restored activity is fully sensitive to ill...

background: to assess accessibility of iodinated salt and urinary iodine concentrations (uic) during pregnancy. this cross-sectional study was carried out between october and december, 2009 in urmia county, west azerbaijan (wa), iran. methods: data on demographic characteristics and iodinated salt accessibility were gathered through a questionnaire at 1st trimester. household salt samples and u...

Gas-phase electron-diffraction data and high-level quantum chemical calculations have been used to study the conformational behaviour of N-azidomethylpyrrolidine. The two most stable conformers with a relative abundance of about 80% at 298 K possess gauche orientation of the azidomethyl group around the C-N(pyr) bond (C-N(azido)gauche with respect to the endocyclic N(pyr)-C bond). This orientat...

A general approach to enantiopure conformationally constrained sugar derived α/β- and α/γ-peptides has been established. Five-membered ring α/β-peptides were synthesized via formyl C-glycofuranosides, easy available from hexose-derived azido-2-equatorial-OH-glycopyranosides by DAST-promoted ring contraction. By means of a regioselective oxidation with TEMPO at C-6 of hexose-derived 3-azido glyc...

The human epidermoid carcinoma cell line A431 has an usually high number of specific saturable receptor sites for the mitogenic polypeptide hormone epidermal growth factor (EGF). When A431 cells were treated with unlabeled EGF in the culture medium, approximately 50% of the EGF specific binding activity was lost within a few hours (receptor down regulation). A comparison of the surface proteins...

Studies with lactoperoxidase showed that a highly reactive intermediate is produced (on the enzyme) from I- and H2O2 which then diffuses from the enzyme and very rapidly and indiscriminately iodinates any Tyr or peptides containing Tyr which are in the same solution. The evidence supporting these conclusions follows. 1) The rate followed the Michaelis-Menten pattern with I- and H2O2 while the c...