Fructose-1,6-bisphosphate aldolase preferentially associates to glyceraldehyde-3-phosphate dehydrogenase in a mixture of cytosolic proteins as revealed by fluorescence energy transfer measurements.

Fluorescence energy transfer measurements were implemented for demonstrating the specific character of the interaction between aldolase and glyceraldehyde-3-phosphate dehydrogenase. The enzymes, labeled with monobromobimane (donor) and fluorescein isothiocyanate (acceptor), respectively, were mixed into a cytosol preparation and energy transfer between the two fluorophores was observed to develop. This observation reflecting a contact between the two enzymes, suggests that despite the presence of a multitude of potential macromolecular partners glyceraldehyde-3-phosphate dehydrogenase and aldolase are capable of recognizing each other in the cytoplasm. The idea that in vivo associations of metabolically sequential enzymes may be of physiological benefits is consistent with this result.