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Aminopeptidase activity from germinated jojoba cotyledons
Plant Physiology
|November 1, 1985
Summary
Researchers isolated a major aminopeptidase from jojoba seeds. This enzyme plays a key role in breaking down seed proteins during cotyledon senescence.
Area of Science:
- Biochemistry
- Plant Science
- Enzymology
Background:
- Jojoba (Simmondsia chinensis) seeds contain reserve proteins.
- Enzymatic degradation is crucial for nutrient mobilization during seed germination and senescence.
Purpose of the Study:
- To isolate and characterize aminopeptidase activities from germinated jojoba cotyledons.
- To investigate the potential physiological role of these enzymes in seed protein breakdown.
Main Methods:
- Enzyme extraction from germinated jojoba cotyledons.
- Separation of aminopeptidase activities using ammonium sulfate precipitation and chromatofocusing.
- Purification and characterization of the major aminopeptidase, including pH optimum, molecular weight, and substrate specificity determination.
Main Results:
- One major and two minor aminopeptidase activities were identified.
- The major aminopeptidase was purified 260-fold, with a pH optimum of 6.9 and a molecular weight of 14,200 Da.
- This enzyme showed activity on specific synthetic substrates and jojoba seed proteins, suggesting a role in globulin reserve protein degradation.
Conclusions:
- A distinct major aminopeptidase was purified from jojoba cotyledons.
- The enzyme's characteristics and substrate specificity indicate its involvement in the breakdown of storage proteins during seed development and senescence.
