PMID: 964243Aug 1, 1976Paper

Pyridoxal 5'-phosphate and the regulation of ornithine decarboxylase activity and stability

European Journal of Biochemistry
J L Clark, J L Fuller


There are two forms of ornithine decarboxylase with respect to pyridoxal 5'-phosphate (pyridoxal-P) affinity in exponentially-growing Swiss 3T3 mouse fibroblasts: form I (Km approximately 10 muM) accounts for 30% of the total activity, and form II (Km approximately 0.4 muM) the remainder. Each form of the enzyme is in rapid equilibrium with ornithine and pyridoxal-P; neither form recognizes the Schiff base between ornithine and pyridoxal-P as a substrate. Total pyridoxal-P concentrations indicate that both forms may normally be at least partially active in vivo. Upon stimulation of 3T3 cells by pituitary growth factors, form I becomes undetectable within 4 h. As total activity increases over 10-fold during this time and continues to increase thereafter, a possible conversion of form I to form II could account for this increase only if the Km change reflects other changes in preexisting enzyme. The rates of cofactor dissociation are apparently the same for each form and neither rate changes with the growth state. Since rapid equilibrium kinetics apply, the forms apparently differ in their rate of cofactor association. The half-lives of the two forms in vivo are the same in unstimulated cells when measured concurrently. Also, the...Continue Reading


Oct 1, 1975·European Journal of Biochemistry·R T Dean
May 1, 1973·Biochemical and Biophysical Research Communications·G Litwack, S Rosenfield
Sep 1, 1974·Archives of Biochemistry and Biophysics·R D Reynolds, S D Thompson
Jan 1, 1972·Advances in Enzyme Regulation·H G Williams-AshmanA Schenone
Jun 1, 1968·Biochemistry·G Litwack, W W Cleland
Apr 16, 1971·Biochemical and Biophysical Research Communications·J S Bond
Oct 1, 1972·Proceedings of the National Academy of Sciences of the United States of America·W A ScottG M Tomkins
Sep 1, 1972·Proceedings of the National Academy of Sciences of the United States of America·A L Goldberg
Dec 19, 1973·Biochimica Et Biophysica Acta·S I Harik, S H Snyder
Jan 1, 1973·Current Topics in Cellular Regulation·N Katunuma
Jan 1, 1974·Annual Review of Biochemistry·D R Morris, R H Fillingame
Jan 28, 1972·Biochimica Et Biophysica Acta·S J FriedmanE S Canellakis
Sep 22, 1965·Biochemical and Biophysical Research Communications·D R Morris, A B Pardee
Apr 1, 1970·Analytical Biochemistry·B Chabner, D Livingston
Jun 1, 1970·Experimental Cell Research·H J Helminen, J L Ericsson
Jul 1, 1968·The Biochemical Journal·A E Pegg, H G Williams-Ashman
Jan 1, 1964·Advances in Enzyme Regulation·O Greengard

❮ Previous
Next ❯


Dec 1, 1982·Neurochemical Research·S I LaitinenR S Piha
Nov 1, 1984·Molecular and Cellular Endocrinology·D LoebL P Bullock
Oct 1, 1978·Proceedings of the National Academy of Sciences of the United States of America·F Landy-Otsuka, I E Scheffler
Nov 1, 1985·Journal of Cellular Physiology·M LindenO Heby
Nov 10, 1981·Biochemistry·M K Haddox, D H Russell
Feb 1, 1979·Experimental Cell Research·J L Clark, S Greenspan
May 15, 1980·Analytical Biochemistry·M K Patterson, M D Maxwell
Jan 15, 1981·Biochimica Et Biophysica Acta·J L MitchellJ M Wilson
Jun 6, 1979·Biochimica Et Biophysica Acta·A E Pegg, S McGill
Aug 11, 1977·Biochimica Et Biophysica Acta·J L Mitchell, D D Carter
Sep 15, 1977·Biochimica Et Biophysica Acta·L S Jefferson, A E Pegg
Oct 8, 1982·Biochimica Et Biophysica Acta·C GuarnieriC M Caldarera
Apr 30, 1981·Biochemical and Biophysical Research Communications·J F RichardsC Bourgeault
Dec 6, 1976·Biochemical and Biophysical Research Communications·J L Clark, J L Fuller

❮ Previous
Next ❯

Related Concepts

Trending Feeds


Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.


Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.


Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.