Original αγα tripeptides containing one β,γ-diamino acid have been synthesized and their conformation determined by extensive NMR and molecular dynamic studies. These studies revealed the presence of a C(9) hydrogen bonded turn around the β,γ-diamino acid which was stabilized by bulky side chains of the preceding residue. This turn can be considered as a mimic of the well-known γ-turn.

In this study, s-triazine rings (or their derivatives) were introduced into a two-dimensional phase-separated mixed monolayer of hydrocarbon-fluorocarbon chains. The diamino-triazine ring facilitated the absorption deoxyribonucleic acid (DNA) molecules in monolayer. diamino ring-containing copolymers which hydrogenated hydrophobic chain was able to form mixed-phase-separated monolayers when com...

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In the title salt, C(5)H(8)N(3) (+)·C(7)H(3)N(2)O(7) (-), the pyridine N atom of the 3,4-diamino-pyridine mol-ecule is protonated. The 3,5-dinitro-salicylate anion shows whole-mol-ecule disorder over two orientations with a refined occupancy ratio of 0.875 (4): 0.125 (4). In the crystal, the cations and anions are connected by inter-molecular N-H⋯O and C-H⋯O hydrogen bonds, forming a three-dime...

We investigated whether phorbol-12-acetate-13-myristate (PMA)-activated human polymorphonuclear leukocytes (PMNs) induce base modifications in target cell DNA in vivo. Human PMNs produced 9.4 +/- 0.8 (SD) nmol of H2O2/10(6) cells during 50 min of exposure to 2 micrograms/ml PMA and 13.7 +/- 2.8 nmol/10(6) cells during exposure to PMA plus 5 mM NaN3. Neither nonstimulated PMNs, nor PMA alone, no...

The (Y , r-diaminobutyric acid and L-(Y) &diaminopropionic acid were synthesized for us by Miss Lillian Alonso, from L-glutamic acid (1) and L-asparagine (2). The diamino acids were included as their hydrochlorides in Krebs’ Ringer-bicarbonate medium, and this was added to the ascitic fluid suspension or to the separated cells or tissues at levels of 15 to 40 mM per liter. The methods of incuba...

In the title compound, C(5)H(8)N(3) (+)·C(7)H(4)NO(4) (-)·C(7)H(5)NO(4), the non-H atoms of the 3,4-diamino-pyridinium cation are coplanar, with a maximum deviation of 0.022 (1) Å. The carboxyl-ate and nitro groups of the 4-nitro-benzoate anion are twisted out of the attached ring planes by dihedral angles of 15.89 (8) and 10.20 (8)°, respectively. In the 4-nitro-benzoic acid mol-ecule, the car...

The antitumor agent, asterriquinone (ARQ) is a known metabolite isolated from the mycelium of Aspergillus terreus IFO 61231). YAMAMOTO et al. reported that ARQ analogues having a 2, 5-dimethoxy-p-benzoquinone moiety (ARQ dimethyl ether: ARQDMe)2,3) and the 2, 5-diamino-p-benzoquinone moiety (diamino ARQ: ARQDA)4) did not show any Cytotoxicity. As reported in our previous communication5), a new ...