title: Secondary structure of endocrine amyloid: infrared spectroscopy of medullary carcinoma of the thyroid.
abstract: Infrared spectroscopic characteristics of deparaffinized tissue sections of the amyloid produced by medullary carcinoma of the thyroid confirm the presence of both beta-sheet and disordered conformations within the deposits. No evidence for alpha-helical structures is found. Amyloid produced by medullary carcinoma of the thyroid thus possesses secondary structural characteristics similar to amyloid of immunoglobulin origin. Infrared spectra were obtained directly from deparaffinized tissue sections, assuring that the chemical structure of amyloid in the recorded spectrum corresponds to that seen microscopically. This structure may or may not correspond to that in vivo, since fixation and dehydration may alter protein secondary structure.
mesh_terms: D000682:Amyloid; D000686:Amyloidosis / Q000378:metabolism*; D006801:Humans; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared; D013964:Thyroid Neoplasms / Q000378:metabolism*
chemical_list: D000682:Amyloid