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Tobacco leaf mesophyll peroxidase. Isolation, purification and some properties
International Journal of Peptide and Protein Research
|July 1, 1979
Summary
Two tobacco isoperoxidases, P1 and P2, were isolated and found to differ in their properties. These enzymes exhibit distinct electrophoretic, catalytic, and physical characteristics.
Area of Science:
- Plant biochemistry
- Enzymology
Background:
- Isoperoxidases play crucial roles in plant physiology.
- Understanding their properties is key to elucidating their functions.
Purpose of the Study:
- To isolate and characterize two distinct isoperoxidases (P1 and P2) from tobacco mesophyll leaves.
- To investigate their biochemical and physical properties.
Main Methods:
- Enzyme isolation using ammonium sulphate precipitation, PAGE, and DEAE-cellulose column chromatography.
- Determination of pH optima and Michaelis constants (Km) for hydrogen peroxide (H2O2).
Main Results:
- Two isoperoxidases, P1 and P2, were successfully isolated.
- P1 and P2 showed different pH optima (7.0 and 7.5, respectively).
- Km values for H2O2 were 1.82 mM for P1 and 0.87 mM for P2, indicating differing catalytic efficiencies.
Conclusions:
- The isolated isoperoxidases P1 and P2 possess distinct electrophoretic profiles.
- Significant differences in catalytic properties (pH optima, Km) were observed between P1 and P2.
- These findings highlight the heterogeneity of isoperoxidases and their varied biochemical roles in tobacco.