Putrescine and spermidine control degradation and synthesis of ornithine decarboxylase in Neurospora crassa

Journal Article · Fri Jul 15 04:00:00 EDT 1988 · J. Biol. Chem.; (United States)

OSTI ID:6840986

Barnett, G R; Seyfzadeh, M; Davis, R H

Neurospora crassa mycelia, when starved for polyamines, have 50-70-fold more ornithine decarboxylase activity and enzyme protein than unstarved mycelia. Using isotopic labeling and immunoprecipitation, we determined the half-life and the synthetic rate of the enzyme in mycelia differing in the rates of synthesis of putrescine, the product of ornithine decarboxylase, and spermidine, the main end-product of the polyamine pathway. When the pathway was blocked between putrescine and spermidine, ornithine decarboxylase synthesis rose 4-5-fold, regardless of the accumulation of putrescine. This indicates that spermidine is a specific signal for the repression of enzyme synthesis. When both putrescine and spermidine synthesis were reduced, the half-life of the enzyme rapidly increased 10-fold. The presence of either putrescine or spermidine restored the normal enzyme half-life of 55 min. Tests for an ornithine decarboxylase inhibitory protein (antizyme) were negative. The regulatory mechanisms activated by putrescine and spermidine account for most or all of the regulatory amplitude of this enzyme in N. crassa.

• Research Organization: Univ. of California, Irvine (USA)
• OSTI ID: 6840986
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 263:20; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINES
AMINO ACIDS
BIOLOGICAL HALF-LIFE
BIOLOGICAL PATHWAYS
BIOSYNTHESIS
CARBON-CARBON LYASES
CARBOXY-LYASES
CARBOXYLIC ACIDS
DECARBOXYLASES
ENZYME ACTIVITY
ENZYMES
FUNGI
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LYASES
NEUROSPORA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORNITHINE
PLANTS
PROTEINS
PUTRESCINE
SPERMIDINE
SYNTHESIS
TRACER TECHNIQUES