scholarly journals Measurement of the number of ornithine decarboxylase molecules in rat and mouse tissues under various physiological conditions by binding of radiolabelled α-difluoromethylornithine

1982 ◽  
Vol 206 (2) ◽  
pp. 311-318 ◽  
Author(s):  
James E. Seely ◽  
Hannu Pösö ◽  
Anthony E. Pegg
Keyword(s):  
Ornithine Decarboxylase ◽  
Rat Liver ◽  
Pyridoxal Phosphate ◽  
Mouse Kidney ◽  
Decarboxylase Activity ◽  
Irreversible Inhibitor ◽  
Ornithine Decarboxylase Activity ◽  
Mouse Tissues ◽  
Mammalian Tissues ◽  
Maximal Induction

The binding of α-difluoromethylornithine, an irreversible inhibitor, to ornithine decarboxylase was used to investigate the amount of enzyme present in rat liver under various conditions and in mouse kidney after treatment with androgens. Maximal binding of the drug occurred on incubation of the tissue extract for 60min with 3μm-difluoromethyl[5-14C]ornithine in the presence of pyridoxal phosphate. Under these conditions, only one protein became labelled, and this corresponded to ornithine decarboxylase, having Mr about 100000 and subunit Mr about 55000. Treatment of rats with thioacetamide or carbon tetrachloride or by partial hepatectomy produced substantial increases in ornithine decarboxylase activity and parallel increases in the amount of enzyme protein as determined by the extent of binding of difluoromethyl[5-14C]ornithine. Similarly, treatment with cycloheximide or 1,3-diaminopropane greatly decreased both the enzyme activity and the amount of difluoromethyl-[5-14C]ornithine bound to protein. In all cases, the ratio of drug bound to activity was 26fmol/unit, where 1 unit corresponds to 1nmol of substrate decarboxylated in 30min. These results indicate that even after maximal induction of the enzyme in rat liver there is only about 1ng of enzyme present per mg of protein. When mice were treated with androgens there was a substantial increase in renal ornithine decarboxylase activity, the magnitude of which depended on the strain. There was an excellent correspondence between the amount of activity present and the capacity to bind labelled α-difluoromethylornithine in the mouse kidney extracts, but in this case the ratio of drug bound to activity was 14fmol/unit, suggesting that the mouse enzyme has a higher catalytic-centre activity. After androgen induction, the mouse kidney extracts contain about 170ng of enzyme/mg of protein. These results indicate that titration with α-difluoromethylornithine provides a valuable method by which to quantify the amount of active ornithine decarboxylase present in mammalian tissues, and that the androgen-treated mouse kidney is a much better source for purification of the enzyme than is rat liver.

scholarly journals Role of pyridoxal phosphate in mammalian polyamine biosynthesis. Lack of requirement for mammalian S-adenosylmethionine decarboxylase activity

1977 ◽  
Vol 166 (1) ◽  
pp. 81-88 ◽  
Author(s):  
A E Pegg
Keyword(s):  
Ornithine Decarboxylase ◽  
Pyridoxal Phosphate ◽  
Vitamin B ◽  
Decarboxylase Activity ◽  
Deficient Diet ◽  
Polyamine Biosynthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Ornithine Decarboxylase Activity

1. Polyamine concentrations were decreased in rats fed on a diet deficient in vitamin B-6. 2. Ornithine decarboxylase activity was decreased by vitamin B-6 deficiency when assayed in tissue extracts without addition of pyridoxal phosphate, but was greater than in control extracts when pyridoxal phosphate was present in saturating amounts. 3. In contrast, the activity of S-adenosylmethionine decarboxylase was not enhanced by pyridoxal phosphate addition even when dialysed extracts were prepared from tissues of young rats suckled by mothers fed on the vitamin B-6-deficient diet. 4. S-Adenosylmethionine decarboxylase activities were increased by administration of methylglyoxal bis(guanylhydrazone) (1,1′-[(methylethanediylidine)dinitrilo]diguanidine) to similar extents in both control and vitamin B-6-deficient animals. 5. The spectrum of highly purified liver S-adenosylmethionine decarboxylase did not indicate the presence of pyridoxal phosphate. After inactivation of the enzyme by reaction with NaB3H4, radioactivity was incorporated into the enzyme, but was not present as a reduced derivative of pyridoxal phosphate. 6. It is concluded that the decreased concentrations of polyamines in rats fed on a diet containing vitamin B-6 may be due to decreased activity or ornithine decarboxylase or may be caused by an unknown mechanism responding to growth retardation produced by the vitamin deficiency. In either case, measurements of S-adenosylmethionine decarboxylase and ornithine decarboxylase activity under optimum conditions in vitro do not correlate with the polyamine concentrations in vivo.

Puromycin Stimulation of Rat Liver Ornithine Decarboxylase Activity

Nature ◽  
1973 ◽  
Vol 241 (5387) ◽  
pp. 275-277 ◽  
Author(s):  
WILLIAM T. BECK ◽  
RILL ANN BELLANTONE ◽  
E. S. CANELLAKIS
Keyword(s):  
Ornithine Decarboxylase ◽  
Rat Liver ◽  
Decarboxylase Activity ◽  
Ornithine Decarboxylase Activity ◽  
Stimulation Of

scholarly journals Inhibition of Ornithine Decarboxylase Activity in Mouse Kidney by Administration of Diamines.

1979 ◽  
Vol 33b ◽  
pp. 537-540 ◽  
Author(s):  
Lo Persson ◽  
Elsa Rosengren ◽  
Siv Osterman-Golkar ◽  
Dan Segerbäck ◽  
Curt R. Enzell ◽  
...  
Keyword(s):  
Ornithine Decarboxylase ◽  
Mouse Kidney ◽  
Decarboxylase Activity ◽  
Ornithine Decarboxylase Activity

scholarly journals Effects of aliphatic diamines on rat liver ornithine decarboxylase activity

1978 ◽  
Vol 170 (3) ◽  
pp. 651-660 ◽  
Author(s):  
A E Pegg ◽  
C Conover ◽  
A Wrona
Keyword(s):  
Ornithine Decarboxylase ◽  
Rat Liver ◽  
Diamine Oxidase ◽  
Normal Values ◽  
Intraperitoneal Administration ◽  
Oxidase Inhibitor ◽  
Decarboxylase Activity ◽  
Rapid Loss ◽  
Polyamine Synthesis ◽  
Ornithine Decarboxylase Activity

Rat liver ornithine decarboxylase activity was decreased by administration of putrescine (1,4-diaminobutane) or other diamines, including 1,3-diaminopropane, 1,5-diaminopentane and 1,6-diaminohexane. This effect was seen in control rats and in rats in which hepatic ornithine decarboxylase activity had been increased by administration of growth hormone (somatotropin) or thioacetamide. Loss of activity was not dependent on the conversion of putrescine into polyamines and was short-lived. Within 6h after intraperitoneal administration of 0.8 mmol/kg body wt., ornithine decarboxylase activity had returned to normal values. This return correlated with the rapid loss of the diamines from the liver, and the decrease in activity could be slightly prolonged by treatment with aminoguanidine, a diamine oxidase inhibitor. A decrease in ornithine decarboxylase activity by these diamines was accompanied by the accumulation in the liver of a nondiffusible inhibitor that decreased the activity of a purified ornithine decarboxylase preparation. The possibility that administration of non-physiological diamines that are not converted into polyamines might be useful for the inhibition of polyamine synthesis is discussed.

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