The amyloid P-component (protein AP): an integral part of the amyloid substance?

The P-component of amyloid (protein AP) appears to be present in all types of amyloid substance regardless of the clinical category of amyloidosis or the chemical class of the amyloid fibril. The role of protein AP in the formation of amyloid substance has not been established. In a patient with primary amyloidosis, significant amounts of protein AP were found closely associated with the amyloid fibril proteins and was released from the latter only after dissociation and reduction of the amyloid fibril preparation. EDTA seemed to be very effective in releasing protein AP, and it is thought that the close association between the amyloid fibrils and protein AP is calcium-dependent. The very close association between the amyloid fibrils and protein AP suggests that the latter is an integral part of the amyloid substance.