Related Experiment Videos
Oil-bodies as substrates for lipolytic enzymes
1Laboratoire de Lipolyse Enzymatique, Institut de Biologie Structurale et Microbiologie, Marseille, France.
Biochimica Et Biophysica Acta
|March 30, 2001
Summary
Plant seed oil-bodies, containing triacylglycerols (TAGs), are readily hydrolyzed by lipases during germination. Research shows the protective coat doesn't prevent lipase access, suggesting direct TAG breakdown supports seedling growth.
Area of Science:
- Biochemistry
- Plant Biology
- Lipid Metabolism
Background:
- Plant seeds store energy as triacylglycerols (TAGs) within oil-bodies.
- Oil-bodies are composed of a lipid core enclosed by phospholipids and proteins.
- Lipase-mediated TAG hydrolysis fuels seedling growth during germination.
Purpose of the Study:
- To investigate how lipases access and hydrolyze TAGs within oil-bodies.
- To determine if the oil-body coat impedes lipase activity.
- To understand the mechanism of oil-body lipolysis in plants.
Main Methods:
- In vitro lipolysis assays using purified lipases and almond oil-bodies.
- pH-stat technique to measure free fatty acid release.
- Comparison of lipase activity on oil-bodies versus emulsified oil.
- Kinetic studies and assessment of phospholipase activity.
Main Results:
- All tested lipases released free fatty acids from oil-bodies.
- Lipase activity on oil-bodies ranged from 18-38% of activity on emulsified oil.
- No correlation found between phospholipase activity and TAG hydrolysis efficiency.
- Oil-bodies function as substrates similar to other proteolipid organelles.
Conclusions:
- The protein/phospholipid coat of oil-bodies does not prevent lipase access to TAGs.
- Plant lipases can directly hydrolyze oil-bodies in vitro.
- Seedling lipolysis likely occurs without prior degradation of the oil-body coat.