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Essential arginyl residues in yeast phosphoglyceromutase
Journal of Biochemistry
|October 1, 1977
Summary
Yeast phosphoglyceromutase inactivation by 1,2-cyclohexanedione modifies arginyl residues crucial for substrate binding. The enzyme
Area of Science:
- Biochemistry
- Enzymology
Background:
- Yeast phosphoglyceromutase catalyzes a key step in glycolysis.
- Understanding enzyme active site residues is crucial for enzyme function studies.
Purpose of the Study:
- To investigate the role of arginyl residues in yeast phosphoglyceromutase activity.
- To elucidate the structural basis of substrate binding and enzyme catalysis.
Main Methods:
- Chemical modification of yeast phosphoglyceromutase using 1,2-cyclohexanedione.
- Enzyme activity assays and protection experiments with 3-phosphoglycerate.
- Reactivation studies using hydroxylamine.
Main Results:
- Inactivation correlated with modification of six arginyl residues per enzyme molecule.
- Four arginyl residues per subunit are essential for substrate (3-phosphoglycerate) binding.
- Enzyme activity was reversibly restored upon hydroxylamine treatment.
- Reactivity of active site lysyl residues was reduced, suggesting proximity to arginyl residues.
Conclusions:
- Arginyl residues are critical for both substrate binding and catalysis in yeast phosphoglyceromutase.
- The active site likely contains closely positioned lysyl and arginyl residues.
- Chemical modification provides insights into enzyme structure-function relationships.