Non-native glyceraldehyde-3-phosphate dehydrogenase can be an intrinsic component of amyloid structures

Interactions between different forms of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and amyloid-beta peptide (1-42) were investigated by direct (surface plasmon resonance) and indirect (kinetics of spontaneous and GroEL/S-assisted reactivation of denatured GAPDH) methods. It was demonstrated that non-native forms of GAPDH obtained by different ways (cold denaturation, oxidation of the enzyme, and its unfolding in guanidine hydrochloride) efficiently bind to soluble amyloid-beta peptide (1-42) yielding a stable complex. Native tetrameric GAPDH does not interact with soluble amyloid-beta peptide (1-42), neither non-native forms of GAPDH interact with aggregated amyloid-beta peptide (1-42). The results suggest that non-native GAPDH species can be involved in the formation of amyloid structures during Alzheimer's disease, binding to soluble amyloid-beta peptide (1-42).