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A unique ascorbate peroxidase active component in the cyanobacterium Synechococcus PCC 7942 (R2)
A Rozen1, R Mittler, Y Burstein
1Department of Agricultural Botany, Hebrew University of Jerusalem, Rehovot.
Free Radical Research Communications
|January 1, 1992
Summary
This study purified and characterized ascorbate peroxidase active component (APAC) from Synechococcus PCC 9742 cells. The enzyme demonstrated remarkable stability and a strong correlation between activity and iron content.
Area of Science:
- Biochemistry
- Enzymology
- Microbiology
Background:
- Ascorbate peroxidase is crucial for antioxidant defense in plants and algae.
- Understanding its properties in cyanobacteria like Synechococcus PCC 9742 provides insights into cellular protection mechanisms.
Purpose of the Study:
- To purify and characterize the ascorbate peroxidase active component (APAC) from Synechococcus PCC 9742.
- To investigate the stability, iron content correlation, and kinetic properties of APAC.
Main Methods:
- Ion exchange chromatography on DEAE cellulose.
- Ultrafiltration and reversed-phase high-pressure liquid chromatography (RP-HPLC).
- Electron spin resonance (E.S.R.) spectroscopy and amino acid composition analysis.
Main Results:
- APAC was successfully purified and exhibited exceptional stability to heat, acidic pH, and proteolytic digestion.
- A strong correlation was observed between APAC activity and its iron content.
- E.S.R. spectroscopy indicated iron presence, and kinetic studies revealed high affinities for H2O2 and ascorbate.
Conclusions:
- The purified APAC from Synechococcus PCC 9742 is a highly stable enzyme with significant iron content.
- Its properties suggest an important role in cellular antioxidant defense within this cyanobacterium.