[Quaternary structure of murine amyloid fibrils: fibril dissociation following exposure to sodium dodecyl sulfate and alkali].

Purified amyloid fibrils from the spleens of CBA mice with casein-induced amyloidosis were dissociated in 0.1 N NaOH or 2% sodium dodecyl sulfate (SDS). Amyloid fibrils were found to dissociate in 0.1 N NaOH to stable subunits with a molecular weight about 500 000 as shown by gel chromatography. Both fibrils and their high-molecular subunits were dissociated in 2% SDS to polypeptides of two types whos molecular weight amounted to 11 000 and 15 000, respectively, as revealed by electrophoresis in polyacrylamide gel in the presence of SDS. It is assumed that interchain disulfide bonds do not play a role in the maintenance of the quaternary structure of the amyloid fibrils.