Studies on the mechanisms of ornithine decarboxylase in vitro inactivation

Zuretti, Maria Franca; Gravela, E

doi:10.1016/0167-4838(83)90311-4

Cited by 24 publications

(14 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The initial events in degradation of ODC and the cellular compartments and proteinases involved in this process are unknown, though several mechanisms have been proposed. The primary steps in ODC degradation may involve reactions with antizyme [30][31][32] and/or reversible inactivation by the formation of mixed disulphides [33,34]. It has also been suggested that antizyme recycles during the degradation of ODC in a manner similar to the ubiquitin-dependent proteolysis in reticulocytes [30,31].…”

Section: Discussionmentioning

confidence: 99%

Post-translational arginylation of ornithine decarboxylase from rat hepatocytes

Kopitz

Rist

Bohley

1990

Biochemical Journal

View full text Add to dashboard Cite

Ornithine decarboxylase (ODC) was purified 6500-fold from NMRI mouse kidneys under conditions designed to inhibit degradation by proteinases. The enzyme was homogeneous by SDS/polyacrylamide-gel electrophoresis, and the specific activity was among the highest reported. The yield was 70%. A monoclonal antibody against this preparation was generated and used in studies to investigate the half-life of ODC in cultured rat hepatocytes labelled with [35S]methionine. This value was 39 +/- 4 min and was unchanged when either NH4Cl (as a lysosomotropic agent) or leupeptin (as a lysosomal proteinase inhibitor) was added to the culture medium. Thus the intracellular turnover of ODC in cultured hepatocytes occurs mainly in extra-lysosomal compartments. Arginylation of rat ODC was investigated in vitro by incubation with L-[3H]arginyl-tRNA, and the incorporation of the label was compared with that of total cytosolic proteins. Arginylated ODC had a specific radioactivity 8600 times that of the bulk of cytosolic protein. Edman degradation of this ODC showed that the post-translational arginylation occurred only at the alpha-amino end of the enzyme. The inhibitor of arginyl-tRNA:protein arginyltransferase (EC 2.3.2.8), L-glutamyl-L-valyl-L-phenylalanine, increased the half-life of ODC in cultured hepatocytes from 39 min to more than 90 min. The possible significance of the preferential post-translational arginylation of ornithine decarboxylase to its rapid turnover is discussed.

show abstract

Section: Discussionmentioning

confidence: 99%

Post-translational arginylation of ornithine decarboxylase from rat hepatocytes

Kopitz

Rist

Bohley

1990

Biochemical Journal

View full text Add to dashboard Cite

show abstract

“…It may therefore be speculated that a high level of phosphorylcholine may serve several cellular functions: (a) as a precursor of lecithin biosynthesis (Ansell and Spanner, 1977); (b) as a cellular store of choline, as has been suggested (Ishidate et al, 1982b), and perhaps of phosphate as well; and (c) as demonstrated presently, as an inhibitor of ODC activity. This inhibition may be involved in the posttranslational control of ODC activity along with other proposed mechanisms (Canellakis et al, 1981;Mitchell, 1981;Zuretti and Gravela, 1983).…”

Section: Discussionmentioning

confidence: 97%

Reciprocal Regulation of Ornithine Decarboxylase and Choline Kinase Activities by Their Respective Reaction Products in the Developing Rat Cerebellar Cortex

Gilad

1984

Journal of Neurochemistry

View full text Add to dashboard Cite

Changes in the activity of choline kinase were measured in the cerebellum during development. Early transient increase was found in the enzyme activity just prior to and during birth. This period of increase did not coincide with the periods of transient elevation in ornithine decarboxylase and choline acetyltransferase previously observed in the developing cerebellum. The effects of the naturally occurring polyamines (putrescine, spermidine, and spermine) on choline kinase and choline acetyltransferase activities, and of phosphorylcholine (the product of the reaction catalyzed by choline kinase) on ornithine decarboxylase and choline acetyltransferase activities, were also examined. Choline acetyltransferase activity was not influenced by either polyamines or phosphorylcholine. However, choline kinase activity from 7-day-old, but not from adult, cerebellum was increased 25% in the presence of 4 mM spermine. In contrast, low spermidine concentrations (less than 2 mM) inhibited choline kinase activity selectively in 7-day-old cerebellum. Ornithine decarboxylase activity from 7-day-old cerebellum was inhibited in a concentration-dependent manner by phosphorylcholine. The present data together with other previous reports suggest that: (a) polyamines may play a role in choline utilization during development via their regulation of choline kinase activity, on the one hand, and of acetylcholinesterase activity on the other; and (b) during development, a reciprocal regulation of choline kinase and ornithine decarboxylase activities by their respective reaction products may exist, whereby choline kinase activity is regulated in a complex manner by polyamines and, in turn, ornithine decarboxylase is inhibited by phosphorylcholine.

show abstract

“…It has been suggested that intramolecular or extramolecular thiol-disulfide exchange reactions may play a role in regulating the degradation rate of ornithine decarboxylase [4]. Different mechanisms involving direct [5] or Fez +-mediated [17] effects of microsomal fractions have been proposed to explain such oxidative reactions. Here, we show that L-ornithine induces a microsome-independent oxidation of ornithine decarboxylase in the absence of thiol-reducing agents in vitro.…”

Section: Discussionmentioning

confidence: 99%

“…Full catalytic activity of mammalian ornithine decarboxylase in vitro is believed to be strongly dependent on low-molecular-mass thiols, and, more particularly, on dithiols such as dithiothreitol. In the absence of an exogenous thiol, the enzyme has been reported to loose activity and to polymerize However, a recent report that the ornithine decarboxylase activity in a lOOOOOxg supernatant of rat liver was quite stable when incubated at 37OC without thiol addition [5], prompted us to re-examine the role of dithiothreitol on the stability of ornithine decarboxylase activity both upon storage and during enzyme assays, using two different sources of enzyme.…”

mentioning

confidence: 99%

l-Ornithine-induced inactivation of mammalian ornithine decarboxylase in vitro

Danzin¹,

Persson

1987

Eur J Biochem

View full text Add to dashboard Cite

Partially purified ornithine decarboxylase, isolated from the liver of thioacetamide-treated rats, is stable in the absence of added low-molecular-mass thiols or other reducing agents. However, under these conditions, the enzyme is rapidly inactivated upon incubation with L-ornithine or L-2-methylornithine. The inactivation process follows first-order kinetics, and saturation kinetics are observed. Rapid recovery of activity is observed after subsequent additon of dithiothreitol. As distinct from L-ornithine, D-ornithine, putrescine, spermidine, or spermine do not produce inactivation of ornithine decarboxylase. Very similar results are obtained with pure ornithine decarboxylase isolated from androgen-stimulated mouse kidney, stabilized with a rat liver extract.

show abstract

Studies on the mechanisms of ornithine decarboxylase in vitro inactivation

Cited by 24 publications

References 13 publications

Post-translational arginylation of ornithine decarboxylase from rat hepatocytes

Post-translational arginylation of ornithine decarboxylase from rat hepatocytes

Reciprocal Regulation of Ornithine Decarboxylase and Choline Kinase Activities by Their Respective Reaction Products in the Developing Rat Cerebellar Cortex

l-Ornithine-induced inactivation of mammalian ornithine decarboxylase in vitro

Contact Info

Product

Resources

About