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Partial purification and properties of sheep serum "A'-esterases
Biochemical Pharmacology
|August 1, 1983
Summary
Sheep serum "A"-esterase activity, primarily found in high-density lipoprotein (HDL) fractions, was partially purified. Studies suggest multiple enzyme forms exist within HDL2, with activity dependent on Ca2+.
Area of Science:
- Biochemistry
- Enzymology
- Lipoprotein Research
Background:
- Serum esterases play crucial roles in xenobiotic metabolism.
- High-density lipoproteins (HDL) are known to contain various enzymatic activities.
- Understanding esterase localization and properties is vital for biochemical and toxicological studies.
Purpose of the Study:
- To investigate the localization of sheep serum
- -esterase activity.
- To partially purify and characterize these enzymes.
- To explore the relationship between esterase activity and HDL subclasses.
Main Methods:
- Substrate assays using paraoxon and pirimiphos-methyl.
- Lipoprotein fractionation of sheep serum.
- Preparative polyacrylamide gel electrophoresis for enzyme purification.
- Gel filtration to determine molecular weights.
Main Results:
- Significant
- -esterase activity was localized to the HDL fraction of sheep serum.
- Partially purified preparations revealed a major protein unit resembling HDL core protein.
- Evidence suggests the existence of multiple
- -esterase forms with varying substrate specificities.
- Paraoxonase activity was associated with proteins >200,000 mol. wt, indicating involvement of HDL2.
Conclusions:
- Sheep serum
- -esterase activity is predominantly associated with HDL, likely within HDL2 subclasses.
- The findings suggest heterogeneity among these esterase forms.
- Enzyme activity is dependent on Ca2+, and further research is needed for precise esterase classification.