Biomaterial Database

Congo red dichroism with dispersed amyloid fibrils, an extrinsic cotton effect. 1970

E P Benditt, and N Eriksen, and C Berglund

The spectral absorption, optical rotatory dispresion, and circular dichroism associated with interaction of Congo red dye with partly purified suspensions of amyloid fibril fragments were examined. A set of phenomena consistent with a Cotton effect was found. A nearly identical set of phenomena was obtained with poly-L-lysine in its alpha-helical form. The dichroism seen when Congo red binds to amyloid substance in tissue sections can also be interpreted as a Cotton effect. This suggests that some special conformation, presumably in protein, is present in a major constituent of amyloid. This conformation is not present in gamma globulin, Bence-Jones protein, albumin, fibrinogen, or other proteins tested so far. These and other optical properties of amyloid substance can be used to compare amyloid deposits in different human cases and in different species. Extension of the use of polarization microscopy with other dyes that bind to other substances in tissue sections should permit more exquisite probing of the conformation of important macromolecules in situ in cells and tissues than has hitherto been possible.

UI	MeSH Term	Description	Entries
D007668	Kidney	Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.	Kidneys
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008239	Lysine	An essential amino acid. It is often added to animal feed.	Enisyl,L-Lysine,Lysine Acetate,Lysine Hydrochloride,Acetate, Lysine,L Lysine
D008297	Male		Males
D008859	Microscopy, Polarization	Microscopy using polarized light in which phenomena due to the preferential orientation of optical properties with respect to the vibration plane of the polarized light are made visible and correlated parameters are made measurable.	Microscopy, Polarized Light,Polarization Microscopy,Light Microscopies, Polarized,Light Microscopy, Polarized,Microscopies, Polarization,Microscopies, Polarized Light,Polarization Microscopies,Polarized Light Microscopies,Polarized Light Microscopy
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D009905	Optical Rotatory Dispersion	The method of measuring the dispersion of an optically active molecule to determine the relative magnitude of right- or left-handed components and sometimes structural features of the molecule.	Dispersion, Optical Rotatory,Rotatory Dispersion, Optical
D011108	Polymers	Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).	Polymer
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D002942	Circular Dichroism	A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Circular Dichroism, Vibrational,Dichroism, Circular,Vibrational Circular Dichroism