Data found in literature have reported that bacterial endotoxins may be involved in the inflammatory and pathological processes associated with amyloidosis and Alzheimer's disease (AD). In fact, it has been observed that the chronic infusion of the b

β2‐microglobulin fibrils have been extracted from the femoral head of a patient who has been under chronic haemodialysis for 11 years. The primary structure of the N‐terminal portion of the protein and mass determination by electrospray mass spectrometry demonstrate that β2‐microglobulin, extracted as fibrils by the water extraction procedure, was not glycated and that Asn17 was not deamidated. Limited proteolysis was observed in more than 20 % of β2‐microglobulin molecules and the main cleavage sites were at the C‐terminus of Lys6 and Tyr10. β2‐microglobulin from fibrils has been purified by gel filtration in 6 M Gdn/HCl and submitted to a refolding procedure. The refolding conditions have been determined through the study of the unfolding pathway of the native protein. β2‐microglobulin is stable at neutral pH where it displays a lower tendency to self‐aggregate than in acidic conditions. Pulse dilution and extensive dialysis in refolding buffer at pH 7.5 yields β2‐microglobulin with a tertiary structure identical to that of the native form. The CD spectrum in the near‐ultraviolet region and the spectrum of the intrinsic fluorescence of Trp overlap those of the native protein, but the CD spectrum in the far‐ultraviolet region is affected by the contribution of oligomers created by β2‐microglobulin fragments that reduce the positive light polarisation at 205 nm typical of native β2‐microglobulin.