Biomaterial Database

Induction of circular dichroism of symmetrical porphyrins bound to random coil polypeptides in aqueous solutions. 1993

T Nezu, and S Ikeda

Department of Chemistry, Faculty of Science, Nagoya University, Japan.

Absorption spectra and c.d. spectra have been measured in the region of Soret transition for aqueous solutions of porphine-meso-tetra(4-N-methylpyridinium) (TMpyP) tosylate in the presence of poly-L-glutamic acid, and of sodium porphine-meso-tetra(4-benzenesulphonate) (TPPS) or sodium porphine-meso-tetra(4-benzoate) (TPPC) in the presence of poly-L-lysine, all at high [P]/[D] ratios at neutral pH. The TmpyP-poly-L-glutamic acid system shows essentially no hypochromism and negligibly weak induced c.d., while the TPPS-poly-L-lysine or TPPC-poly-L-lysine system exhibits strong hypochromism and strong induced c.d. The former absorption band slightly shifts to red, but the latter shows a large blue shift. The primary interaction of the porphyrin with the polypeptide is their electrostatic binding. The difference in their interaction must arise from different degrees of hydrophobic interaction, and stronger interaction of TPPS or TPPC with poly-L-lysine would cause most of TPPS ions or all of TPPC ions bound on poly-L-lysine to dimerize, fix rigidly and couple together electronically on fully charged poly-L-lysine.

UI	MeSH Term	Description	Entries
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D011099	Polyglutamic Acid	A peptide that is a homopolymer of glutamic acid.	Polyglutamate
D011107	Polylysine	A peptide which is a homopolymer of lysine.	Epsilon-Polylysine,Poly-(Alpha-L-Lysine),Epsilon Polylysine
D011166	Porphyrins	A group of compounds containing the porphin structure, four pyrrole rings connected by methine bridges in a cyclic configuration to which a variety of side chains are attached. The nature of the side chain is indicated by a prefix, as uroporphyrin, hematoporphyrin, etc. The porphyrins, in combination with iron, form the heme component in biologically significant compounds such as hemoglobin and myoglobin.	Porphyrin
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
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
D012996	Solutions	The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)	Solution
D013053	Spectrophotometry	The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.
D014867	Water	A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Hydrogen Oxide
D046911	Macromolecular Substances	Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.	Macromolecular Complexes,Macromolecular Compounds,Macromolecular Compounds and Complexes,Complexes, Macromolecular,Compounds, Macromolecular,Substances, Macromolecular