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Pteridine biosynthesis and nitric oxide synthase in Physarum polycephalum
G Werner-Felmayer1, G Golderer, E R Werner
1Institute for Medical Chemistry and Biochemistry, University of Innsbruck, Austria.
The Biochemical Journal
|November 15, 1994
Summary
Physarum polycephalum produces tetrahydrobiopterin and expresses nitric oxide synthase (NOS) activity. NOS activity peaks during mitosis, suggesting a link between NOS and cell division in this slime mold model.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Physarum polycephalum, an acellular slime mold, is a model for synchronous cell cycle events.
- It releases isoxanthopterin, related to tetrahydrobiopterin, a cofactor for nitric oxide synthases (NOS).
Purpose of the Study:
- To investigate Physarum's pteridine biosynthesis and nitric oxide synthase (NOS) activity.
- To explore the relationship between NOS activity and the cell cycle in Physarum.
Main Methods:
- Biochemical characterization of purified Physarum NOS.
- Analysis of pteridine biosynthesis and NOS activity during the Physarum cell cycle.
Main Results:
- Physarum synthesizes significant tetrahydrobiopterin and expresses NOS activity.
- A unique combination of enzymes for pteridine and folic acid biosynthesis was detected.
- Purified Physarum NOS requires NADPH, tetrahydrobiopterin, and flavins, and is independent of Ca2+.
- NOS activity exhibits cell-cycle-dependent fluctuations, peaking during mitosis.
Conclusions:
- Physarum possesses a distinct pteridine biosynthesis pathway and expresses functional NOS.
- NOS activity in Physarum is linked to mitosis, highlighting its potential role in cell division.