ISSN:
1572-8927
Keywords:
Partial molar volumes
;
partial molar heat capacities
;
D-α-manno-naphtho-18-crown-6-ether
;
calix[4]resorcinarene
;
Peptides: Ala–Ala, Ala–Glu, Ala-Ser, Ser-Leu
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Densities and specific heat capacities of ternary aqueous systems containing a dipeptide (alanyl-alanine, alanyl-glutamic acid, alanyl-serine or L-seryl-L-leucine) and a macrocycle (D-α-manno-naphtho-18-crown-6-ether or 2,8,14,20-tetrakis[-methyl (aminoformyl)]-4,6,10,12,16,18,22,24-octahydroxycalix[4]arene) were determined at 25°C by flow densimetry and flow calorimetry. The partial molar volume and heat capacity of transfer of a macrocycle from water to the dipeptide solution was determined as a function of the dipeptide concentration. Positive values for transfer volumes and transfer heat capacities are observed with all the solutions studied. With the crown ether, except for alanyl-glutamic acid where a 1:1 complex is clearly evidenced due to specific interactions of the side-chain functional group of the peptide with the crown ether, no stoichiometric complexes are confirmed and the partial molar quantities of transfer increase with the hydrophobic character of the dipeptide. Partial quantities of transfer are smaller with the calixarene than with the crown ether and stoichiometric complexes [calixarene]/[dipeptide] from 2:1 to 1:4 are evidenced, depending on the nature and the concentration of the dipeptide.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1022653222581
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