We have generated a hybrid transgenic mouse line overexpressing both ornithine decarboxylase (ODC) and spermidine/spermine N(1)-acetyltransferase (SSAT) under the control of the mouse metallothionein (MT) I promoter. In comparison with singly transgenic animals overexpressing SSAT, the doubly transgenic mice unexpectedly displayed much more striking signs of activated polyamine catabolism, as e...

The effect of several polyamines on the transport of organic cations [N1-[3H]methylnicotinamide (NMN), [3H]NMN and 3H-tetraethylammonium, ([3H]TEA)] in rabbit renal brush border (BBMV) and basolateral membrane vesicles (BLMV) was studied using a rapid filtration assay. Under pH-driven conditions in BBMV, [3H]NMN transport was cis inhibited approximately 30% by the naturally occurring polyamines...

Ethylene production in apple fruit and protoplasts and in leaf tissue was inhibited by spermidine or spermine. These polyamines, as well as putrescine, inhibited auxin-induced ethylene production and the conversion of methionine and 1-aminocyclopropane-1-carboxylic acid to ethylene. Polyamines were more effective as inhibitors of ethylene synthesis at the early, rather than at the late, stages ...

Ornithine decarboxylase (ODC) is a key enzyme in polyamine biosynthesis. It is a short-lived protein and negatively regulated by its products, polyamines. Its degradation is accelerated by the binding of antizyme, an ODC-inhibitory protein induced by polyamines. To evaluate the physiological importance of antizyme we examined the effect of forced expression of antizyme on cellular ODC and polya...

Tissue-transglutaminase (t-TGase) is a family of calcium-dependent enzymes. A Ca2+-independent soluble enzyme, in addition to t-TGase, capable of incorporating polyamines into proteins was demonstrated in rat intestinal mucosa. The Ca2+-independent enzyme was stimulated 2- to 5-fold by Fe2+ and Co2+ ions but inhibited by Cu2+ and Zn2+ ions. The Ca2+-stimulated t-TGase activity was inhibited by ...

The polyamines, spermidine and spermine, and their diamine precursor, putrescine, constitute a unidirectional biosynthetic pathway whose biosynthetic enzymes and accumulation patterns appear to play important roles in the regulation of growth processes. Concentrations of these compounds in physiological fluids are low or undetectable under normal conditions, are elevated in patients with metast...

Homospermidine synthase (HSS) catalyses the formation of the polyamine homospermidine from 2 mol of putrescine. The general and kinetic properties of purified HSS from Rhodopseudomonas viridis are given and compared with those of the respective enzymes from other sources. The R. viridis enzyme is shown to catalyse a number of side reactions: (I) In the presence of putrescine or spermidine as do...

Estrogenic regulation of gene expression involves interaction of the hormonewith its receptors, which undergostructuraland conformational changes to interact with specific DNA sequences. Putrescine, spermidine, and spermine, are ubiquitous cellular components. We studied the effects of these polyamines on rabbit uterine estrogen receptors by sucrose gradient centrifugation and ligand dissociati...

Biogenic amines putrescine, spermidine and spermine are ubiquitous in nature and have interested researchers because they are essential for cell division and viability, and due to a large body of their pharmacological effects on growth and development in most living cells. The genes and enzymes involved in their biosynthetic pathways are now established and characterized. In recent years, molec...