ABSTRACT
Over 20 types of amyloidosis, systemic and localized, have been identified by the subunit protein in amyloid deposits. Since prognosis and treatment depends on the type of amyloid, it is essential to correctly identify the amyloid protein. A procedure for isolation and chemical typing of amyloid protein in formalin-fixed paraffin-embedded tissue sections using Edman degradation analysis and mass spectroscopy analysis was reported. One should use this procedure to identify almost the entire amino acid sequence of an amyloid immunoglobulin light chain from formalin-fixed paraffin-embedded heart tissue sections of an autopsied patient with primary (AL) amyloidosis. The variable region sequence of the amyloid protein is most homologous to the lambda I light chain subgroup. While previous studies fractionated the guanidine hydrochloride extract from formalin-fixed paraffin embedded tissue sections by reverse phase HPLC before identification of the amyloid protein, no further purification after guanidine hydrochloride extraction was necessary in this case before biochemical identification of the amyloid protein.
