Anion binding to yeast phosphoglycerate kinase.

Area of Science:

• Biochemistry
• Enzymology

Background:

• Yeast phosphoglycerate kinase is a key enzyme in glycolysis.
• Understanding anion binding is crucial for enzyme mechanism studies.

Purpose of the Study:

• To characterize anion binding to yeast phosphoglycerate kinase.
• To determine the relationship between anion charge and binding affinity.

Main Methods:

• Labeling the enzyme's active site thiol with a chromophoric reagent.
• Spectrophotometric monitoring of anion binding.
• Kinetic analysis of enzyme inhibition by anions.

Main Results:

• A linear correlation was observed between anion charge and binding affinity (dissociation constant).
• Highly charged anions like ATP bind more strongly than less charged anions like Cl-.
• The enzyme has approximately one anion binding site per molecule.

Conclusions:

• Anion charge is a primary determinant of binding affinity to yeast phosphoglycerate kinase.
• The binding site is distinct from the active center thiol.
• Methods used provide reliable dissociation constants for enzyme-anion interactions.