The indirect binding of triose-phosphate isomerase to myofibrils to form a glycolytic enzyme mini-complex

• Published in: Biochimica et biophysica acta Vol. 873; no. 1; pp. 127 - 135
• Main Authors: Stephan, Petra, Clarke, Frank, Morton, Don
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 05.09.1986; Elsevier; North-Holland
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Carbohydrate Epimerases - metabolism; Enzyme complex; Enzymes and enzyme inhibitors; Fructose-Bisphosphate Aldolase - metabolism; Fundamental and applied biological sciences. Psychology; Glyceraldehyde-3-Phosphate Dehydrogenases - metabolism; Isomerases; Multienzyme Complexes - metabolism; Myofibril binding; Myofibrils - metabolism; Protein Binding; Rabbits; Triose-phosphate isomerase; Triose-Phosphate Isomerase - metabolism; Myofibril binding; Triose-phosphate isomerase; Enzyme complex; Glycolytic enzyme; Vertebrata; Myofibril; Mammalia; Enzyme; Triosephosphate isomerase; Rabbit; Molecular interaction; Lagomorpha; Striated muscle
• ISSN: 0167-4838; 0006-3002; 1879-2588; 1878-2434
• DOI: 10.1016/0167-4838(86)90198-6

Binding of triose-phosphate isomerase (D-glyceraldehyde-3-phosphate ketol-isomerase, EC 5.3.1.1) to muscle myofibrils depends upon the concurrent binding of either fructose-bisphosphate aldolase (EC 4.1.2.13), glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12) or both of these enzymes together. Thus triosephosphate isomerase does not bind directly to myofibrils but to glycolytic enzymes already bound to the myofibril. This was established using 125I-labelled enzymes, which are required to provied the necessary sensitivity for the measurement of the complex multiphasic adsorption isotherms. In the presence of aldolase, the most stable stoichiometric relationship is two aldolase bound per triose-phosphate isomerase. The results show that not all sites of aldolase or glyceraldehyde-3-phosphate dehydrogenase binding are available for triose-phosphate isomerase binding. Nevertheless, the results suggest the formation under particular circumstances of a minicomplex spanning the catalysis of fructose 1,6-bisphosphate to 3-phosphoglycerate. Such a complex could provide the physical basis of metabolic channeling in which metabolic intermediates are not released from the complex.