We overexpressed a mouse ornithine decarboxylase gene under the control of a constitutive and an estradiol-inducible promoter in Arabidopsis thaliana to increase our understanding of the regulation of polyamine metabolism. Of particular interest was the role of the substrate ornithine not only in the regulation of polyamine biosynthesis, but also in the accumulation of related amino acids in re...

Ornithine decarboxylase (EC 4.1.1.17) has been purified 3,500-fold from the plasmodia of Physarum polycephalum. The purified material exhibited a Km for ornithine of 0.6 mM and Vmax of 20 mumol of CO2 formed per min/mg at 30 degrees C (62 mumol/min/mg at 37 degrees C). It migrated as a single protein and activity species on high pressure liquid chromatography (TSK-3000) in 0.15 M NaCl (Mr = 80,...

Thirteen patients who underwent 40% to 80% removal of their livers had blood samples drawn initially and daily on postoperative days 1 to 7. The enzyme marker of heightened polyamine metabolism, ornithine decarboxylase, and the indicator of DNA synthesis, thymidine kinase, were measured. In addition, the hormones (insulin, glucagon, estradiol and androgen), which in animals are known to reflect...

In a minority of eukaryotic mRNAs, a small functional upstream ORF (uORF), often performing a regulatory role, precedes the translation start site for the main product(s). Here, conserved uORFs in numerous ornithine decarboxylase homologs are identified from yeast to mammals. Most have noncanonical evolutionarily conserved start codons, the main one being AUU, which has not been known as an ini...

BACKGROUND Probiotics seem to possess tumour inhibitory properties, but few studies have investigated their actions on the cell proliferation of normal colonic mucosa. The effects of a probiotic mixture (VSL#3) on polyamine biosynthesis, Ki-67 levels and apoptosis in the normal colon of rats were studied. MATERIALS AND METHODS For a 4-week period, 20 rats were fed a VSL#3 solution and 20 rats...

Normal cells in culture invariably undergo senescence, whereby they cease proliferation after a finite number of doublings. Irreversible changes in gene expression occurred in senescent human fetal lung fibroblasts: a non-cell cycle-regulated mRNA was partially repressed; an unusual polyadenylated histone mRNA was expressed; although serum induced c-H-ras, c-myc, and ornithine decarboxylase mRN...

Palmitoylcarnitine, which has been reported to be an inhibitor of calcium-activated, phospholipid-dependent protein kinase (protein kinase C), inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced epidermal ornithine decarboxylase in mouse skin in a dose-dependent manner. Neither acetylcarnitine nor palmitic acid inhibited TPA-caused ornithine decarboxylase induction. In addition, palmit...

A protein inhibitor to ornithine decarboxylase, antizyme, was purified to homogeneity, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, about 600,000-fold with a 15% yield from the liver cytosol of putrescine-treated rats. Antizyme was very labile but markedly stabilized in the presence of Tween 80 and 2-mercaptoethanol. The apparent molecular weight of antizyme was deter...

K-252a, a kinase inhibitor isolated from the culture broth of Nocardiopsis sp., selectively inhibits the actions of nerve growth factor (NGF) on PC 12 cells. At a concentration of 200 nM, K-252a prevents neurite generation initiated by NGF, but not neurite generation produced by fibroblast growth factor or outgrowth produced by dibutyryl cAMP. K-252a also inhibits the induction of ornithine dec...

To determine the minimum requirements for substrate recognition and processing by proteasomes, the functional elements of a ubiquitin-independent degradation tag were dissected. The 37-residue C-terminus of ornithine decarboxylase (cODC) is a native degron, which also functions when appended to diverse proteins. Mutating the cysteine 441 residue within cODC impaired its proteasome association i...