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Budding Yeast Protein Extraction and Purification for the Study of Function, Interactions, and Post-translational Modifications
Published on: October 30, 2013
ISOLATION OF HEXOKINASE FROM BAKER'S YEAST
L Berger1, M W Slein, S P Colowick
1Department of Pharmacology, Washington University School of Medicine, St. Louis.
The Journal of General Physiology
|October 30, 2009
Summary
Researchers isolated hexokinase from baker's yeast using alcohol fractionation, achieving a 30-fold increase in specific activity. The crystalline enzyme efficiently transfers phosphate from ATP to sugars, requiring magnesium ions for activity.
Area of Science:
- Biochemistry
- Enzymology
- Protein Chemistry
Background:
- Hexokinase is a crucial enzyme in glucose metabolism.
- Understanding its properties is vital for metabolic research.
- Previous methods for hexokinase isolation were less efficient.
Purpose of the Study:
- To describe an improved method for isolating hexokinase from baker's yeast.
- To characterize the kinetic and stability properties of the purified enzyme.
Main Methods:
- Isolation via alcohol fractionation of baker's yeast extract.
- Crystallization of the enzyme using ammonium sulfate.
- Enzyme activity assays with various sugar substrates and conditions.
Main Results:
- A 30-fold increase in hexokinase specific activity was achieved.
- The crystalline enzyme demonstrated efficient phosphate transfer from ATP to glucose, fructose, and mannose.
- Magnesium ions were essential for activity; fluoride showed no inhibition under specific conditions.
- Enzyme stability was enhanced by other proteins (insulin, albumin) and substrate presence during inactivation studies.
Conclusions:
- The described method yields highly purified and crystalline hexokinase.
- The enzyme exhibits specific substrate preferences and cofactor requirements.
- Hexokinase stability is influenced by protein interactions and substrate binding, offering insights into enzyme preservation.
