1. Ornithine decarboxylase activity is stimulated in high-density HeLa-cell cultures by dilution of or replacement of spent culture medium with fresh medium containing 10% (v/v) horse serum. 2. After stimulation, ornithine decarboxylase activity reaches a peak at 4-6h, then rapidly declines to the low enzyme activity characteristic of quiescent cultures, where it remains during the remainder of...

1,1-Diamino-2,2-dinitroethene (FOX-7) reacts readily with copper nitrate in an aqueous solution of potassium hydroxide to form pea green Cu(FOX)(2)(H(2)O)(2) (5). FOX-7 complexes of copper and nickel supported by a variety of diamines including Cu(en)(2)(FOX)(2)(H(2)O) (1), Cu(pn)(2)(FOX)(2) (2), Cu(bipy)(FOX)(2)(H(2)O)(4) (3a), Cu(bipy)(2)(FOX)(2)(H(2)O)(2.5) (3b), Cu(bipy)(FOX)(2)(DMSO)(2)·2D...

The Arabidopsis thaliana open reading frame At4g20960 predicts a protein whose N-terminal part is similar to the eubacterial 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate deaminase domain. A synthetic open reading frame specifying a pseudomature form of the plant enzyme directed the synthesis of a recombinant protein which was purified to apparent homogeneity and was shown by NMR s...

The title compound, [Zn(C(7)H(3)NO(4))(C(6)H(6)N(4)S(2))(H(2)O)]·4H(2)O, assumes a distorted octa-hedral coordination geometry around the Zn(2+) cation, formed by a diamino-bithia-zole (DABT) mol-ecule, a pyridine-2,6-dicarboxyl-ate anion and a water mol-ecule. The pyridine-2,6-dicarboxyl-ate anion chelates to the Zn(II) atom with a facial configuration. Within the chelating DABT ligand, the tw...

Helix formation in a 17-residue alanine-lysine peptide and analogous peptides with specific lysine --> X substitutions, where X is 2,3-diamino-L-propionic acid, 2, 4-diamino-L-butyric acid or L-ornithine, have been examined using circular dichroism measurements. The dependence of helix content on X, its position in the sequence, and the number of lysine --> X substitutions are reasonably well d...