Apparent co-operativity for highly concentrated Michaelian and allosteric enzymes

Area of Science:

• Biochemistry
• Enzymology
• Biophysics

Background:

• Enzyme kinetics are crucial for understanding cellular processes.
• High enzyme concentrations can alter enzyme behavior.
• Allosteric enzymes exhibit complex regulatory mechanisms.

Purpose of the Study:

• To quantitatively analyze the effect of high enzyme concentration on velocity curves for Michaelian and allosteric enzymes.
• To explore the implications for enzyme function in vivo.
• To compare amplification and co-operativity properties.

Main Methods:

• Quantitative analysis of enzyme velocity curves.
• Modeling of Michaelian and simple allosteric enzyme kinetics.
• Investigation at physiological and high enzyme concentrations.

Main Results:

• Michaelian enzymes exhibit significant amplification at physiological concentrations, comparable to allosteric enzymes.
• Apparent co-operativity, indicated by Hill coefficients, can exceed the number of binding sites.
• Allosteric interactions are necessary for achieving both positive and negative apparent co-operativities.

Conclusions:

• High enzyme concentrations reveal inherent amplification in Michaelian enzymes.
• Allosteric interactions provide a unique regulatory capacity for enzymes.
• Understanding these effects is vital for comprehending intersubunit cooperation in oligomeric enzymes.