Related Experiment Video
Updated: Aug 20, 2026

Direct Detection of the Acetate-forming Activity of the Enzyme Acetate Kinase
Published on: December 19, 2011
A model for the behaviour of phosphorylase b. The generation of different binding sites via intermediate enzymatic
Abstract:
The model given in this paper can be applied to enzymatic systems which have more than two conformational states in equilibrium and which clearly exhibit heterogeneity in the binding of one ligand. The model we propose makes possible quantitative interpretation of our experimental results and of those of many other workers as well. In some cases calorimetric, dialysis and kinetic magnitudes, when plotted against ligand concentration, give multiregional or "stepwise" curves. We suggest that such a behaviour arises because total occupation of one class of binding sites completely moves the enzyme towards a different conformational state in which the affinity for the ligand is greatly increased by the formation of a new class of binding sites. Our calorimetric results for the interaction between some nucleotides and phosphorylase b closely conform to our model.
Related Concept Videos
Induced-fit Model
Enzymes exhibit substrate specificity, meaning that they can only bind to certain substrates. This is mainly determined by the shape and chemical characteristics of...
Ligand Binding and Linkage
Cooperative Allosteric Transitions
Protein Kinases and Phosphatases
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
ATP Synthase: Mechanism
Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...

