scholarly journals Viscoelastic Properties of Dilute Solutions of Unperturbed Chain Polymer and Poly-L-, Copoly-DL-Amino Acids

1966 ◽  
Vol 15 (152) ◽  
pp. 302-306 ◽  
Author(s):  
Hidejiro TANAKA ◽  
Akio SAKANISHI ◽  
Motozo KANEKO ◽  
Jiro FURUICHI
Keyword(s):  
Amino Acids ◽  
Viscoelastic Properties ◽  
Dilute Solutions ◽  
Chain Polymer

The Viscoelastic Properties of Dilute Solutions of Polystyrene in Toluene

1964 ◽  
Vol 68 (5) ◽  
pp. 1072-1078 ◽  
Author(s):  
G. Harrison ◽  
J. Lamb ◽  
A. J. Matheson
Keyword(s):  
Viscoelastic Properties ◽  
Dilute Solutions

scholarly journals Viscoelastic Properties of Dilute Solutions of Random Coil Polymer and α-Helix Polymer

1966 ◽  
Vol 15 (153) ◽  
pp. 447-451
Author(s):  
Hidejiro TANAKA ◽  
Akio SAKANISHI ◽  
Motozo KANEKO ◽  
Jiro FURUICHI
Keyword(s):  
Viscoelastic Properties ◽  
Random Coil ◽  
Dilute Solutions ◽  
Α Helix

THE COMBINATION OF COPPER WITH AMINO ACIDS, PEPTIDES, AND PROTEINS

1959 ◽  
Vol 37 (1) ◽  
pp. 1033-1048
Author(s):  
J. F. Scaife
Keyword(s):  
Amino Acids ◽  
Nitrogen Atom ◽  
Dissociation Constant ◽  
Protein Molecule ◽  
Copper Salt ◽  
The Other ◽  
Dilute Solutions ◽  
Donor Nitrogen Atom ◽  
Donor Nitrogen ◽  
Made In

By equilibrating solutions containing amino acids, peptides, or proteins with the sparingly soluble copper salt malachite (CuCO3.Cu(OH)2), it has been possible to determine the amount of copper in the solutions complexed to these compounds, and the amount of free copper in the solutions in equilibrium with the complex. The dissociation constant for the copper–glycine complex has been estimated from the data obtained using this system. The nature of the complexes has been deduced both from chemical determinations of the bound copper, and from manometric measurements of the extent of complexing, made in bicarbonate buffers. The simple amino acids have been shown to form complexes of the type CuR2, which are appreciably dissociated in dilute solutions. The degree of complexing is influenced by the nature of the group R. Histidine, tryptophane, and other compounds containing more than one donor nitrogen atom are able to form more than one type of complex with copper. The participation of other nitrogen atoms in complexing is related to their basicities. Glycylglycine is able to bind approximately twice as much copper as glycine, but the other glycine peptides from triglycine to pentaglycine show a reduced and progressively decreasing ability to bind copper.The binding of copper to proteins differs from that of the amino acids, in that the amount of copper bound is independent of the concentration of protein present, for any given concentration of free copper. The several atoms of copper bound to each protein molecule were not all bound with the same affinity.

THE COMBINATION OF COPPER WITH AMINO ACIDS, PEPTIDES, AND PROTEINS

1959 ◽  
Vol 37 (8) ◽  
pp. 1033-1048 ◽  
Author(s):  
J. F. Scaife
Keyword(s):  
Amino Acids ◽  
Nitrogen Atom ◽  
Dissociation Constant ◽  
Protein Molecule ◽  
Copper Salt ◽  
The Other ◽  
Dilute Solutions ◽  
Donor Nitrogen Atom ◽  
Donor Nitrogen ◽  
Made In

By equilibrating solutions containing amino acids, peptides, or proteins with the sparingly soluble copper salt malachite (CuCO3.Cu(OH)2), it has been possible to determine the amount of copper in the solutions complexed to these compounds, and the amount of free copper in the solutions in equilibrium with the complex. The dissociation constant for the copper–glycine complex has been estimated from the data obtained using this system. The nature of the complexes has been deduced both from chemical determinations of the bound copper, and from manometric measurements of the extent of complexing, made in bicarbonate buffers. The simple amino acids have been shown to form complexes of the type CuR2, which are appreciably dissociated in dilute solutions. The degree of complexing is influenced by the nature of the group R. Histidine, tryptophane, and other compounds containing more than one donor nitrogen atom are able to form more than one type of complex with copper. The participation of other nitrogen atoms in complexing is related to their basicities. Glycylglycine is able to bind approximately twice as much copper as glycine, but the other glycine peptides from triglycine to pentaglycine show a reduced and progressively decreasing ability to bind copper.The binding of copper to proteins differs from that of the amino acids, in that the amount of copper bound is independent of the concentration of protein present, for any given concentration of free copper. The several atoms of copper bound to each protein molecule were not all bound with the same affinity.

Apparent molal heat capacities and volumes of amino acids in aqueous polyol solutions

1978 ◽  
Vol 56 (13) ◽  
pp. 1827-1831 ◽  
Author(s):  
Giuseppa DiPaola ◽  
Bernard Belleau
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Transfer Functions ◽  
Heat Capacities ◽  
Side Chains ◽  
Dilute Solutions ◽  
Flow Microcalorimeter ◽  
Regular Increase ◽  
Apparent Molal Heat Capacities

Densities (24 °C) and volumetric specific beats (25 °C) were measured for amino acids (0.05–0.5 m) containing apolar side chains in water, and in aqueous solutions of glycerol, mannitol, sorbitol, NaCl, urea, and Gu•HCl, with a flow densimeter and flow microcalorimeter respectively.The derived apparent molal quantifies and transfer functions of the amino acids in aqueous polyol solutions reveal no specificities which might explain the origin of the unique behavior of polyols in protein systems. However, the study did reveal a regular increase in the structure-making ability of the amino acid as the hydrophobicity of the side chains increased. This structure-making tendency was reduced significantly in dilute solutions of the higher polyols.

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