Related Experiment Video
Updated: Aug 14, 2026

Preparation of Highly Coupled Rat Heart Mitochondria
Published on: September 23, 2010
The theory of diazymes and functional coupling of pyruvate kinase and creatine kinase
1Department of Physiology, Michigan State University, East Lansing 48824.
Abstract:
The physical-chemical principles governing the interactions of enzymes having common metabolic products are presented. Methods for comparing the dissociation rates of the metabolic product and the rates of enzyme-enzyme interaction are given. Using muscle pyruvate kinase (PK) and creatine kinase (CK) as an example, it is shown that the probability of forming an enzyme-product-enzyme complex is much greater than the rate of ATP dissociation from either enzyme. Experimental evidence using 31P-NMR demonstrates that in the presence of both pyruvate kinase and creatine kinase, there is exchange of phosphate between phosphocreatine and phosphoenolpyruvate without a change in the intermediate, ATP. This confirms the formation of a PK.ATP.CK complex in an aqueous solution without enzyme attachment to a substructure. Enzymes capable of forming these mobile clusters are defined as diazymes, and the criteria for their formation are given. The metabolic implications of diazymes are discussed.
Related Concept Videos
Enzymes
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
Catalytically Perfect Enzymes
Introduction to Mechanisms of Enzyme Catalysis
Coupled Reactions
Energy in adenosine triphosphate or ATP molecules is easily accessible to do work. ATP powers the majority of energy-requiring cellular reactions. Cells...
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,...
Chemiosmosis and ATP Synthesis

