Detail of "39455-18-0"

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Spectroscopic and thermodynamic investigations on the binding of azure B to chondroitin sulfate and the structure of the metachromatic dye complex

Spectroscopic and thermodynamic investigations on the binding of azure B to chondroitin sulfate and the structure of the metachromatic dye complex. Hueglin, D.Some chemicals with cas registry numbers like 531-55-5 and 39455-18-0 are also used.; Seiffert, W.; Zimmermann, H. W. (Inst. Phys. Chem., Univ. Freiburg/Br., Freiburg D-7800, Fed. Rep. Ger.). Histochemistry, 86(1), 71-82 (German) 1986. CODEN: HCMYAL. ISSN: 0301-5564. DOCUMENT TYPE: Journal CA Section: 6 (General Biochemistry) The binding of azure B to chondroitin sulfate (CHS) was investigated using absorption spectroscopy. In aq. solns. it is possible to distinguish 3 different dye species with absorption bands at 646, 597, and 555 nm. They were assigned to monomers, dimers, and higher aggregates of azure B, which became bound to CHS as the dye concn. (CD) increased. The short-wavelength band (555 nm) caused metachromasia in stained histol. materials. When satn. occurred, the metachromatic azure B-CHS complex had a 1:1 compn., i.e., each anionic SO4-- and COO--binding site of CHS bound 1 dye cation. The compn. of the satd. metachromatic complex was detd. by spectrophotometric and conductometric titrn. of CHS with azure B, whereas the SO-4 and COO- content of CHS was detd. by conductometric titrn. of CHS-acid with NaOH. The binding isotherm of azure B to CHS was detd. using gel-permeation chromatog. The isotherm could be described by the model of cooperative binding of ligands to linear biopolymers. Good agreement was found between theor. predications and exptl. findings in the range 0 < r < 0.8 (r = the fraction of occupied binding sites). Using a Schwarz plot, the binding consts. of nucleation (Kn = 2.5 ′ 103 M-1) and aggregation (Ka = 1.2 ′ 105 M-1), as well as the cooperativity parameter (q = 50), at 295 K were detd. With increasing CD, the strong cooperativity of the dye binding favored the formation of metachromatic aggregates rather than monomers and dimers. From the temp. dependence of Kq the std. binding enthalpy (DHoq = -20.0 kJ mol-1) and entropy (DSoq = 29.7 JK-1mol-1) of the cooperative dye binding were evaluated. The binding was strongly exothermic and accompanied by a thermodynamically favorable entropy increase, this being typical of hydrophobic interactions. .

Thermodynamic properties of dilution of chondroitin 4-sulfate having tetraalkylammonium counterions

Thermodynamic properties of dilution of chondroitin 4-sulfate having tetraalkylammonium counterions. Tsuge, H.; Kishimoto, H.; Yonese, M. (Pharmaceutical Formulation Research Laboratory, Daiichi Pharmaceutical Co., Ltd., Tokyo 134, Japan). Colloid and Polymer Science, 274(9), 819-825 (English) 1996 Steinkopff. CODEN: CPMSB6. ISSN: 0303-402X. DOCUMENT TYPE: Journal CA Section: 66 (Surface Chemistry and Colloids) Section cross-reference(s): 36, 68 The diln. enthalpies, DdilH, of the tetraalkylammonium chondroitin 4-sulfates (R4NChSA) and polyacrylates (R4NPAA) (R = Me, Et, Pr, Bu) were measured to elucidate the effects of hydrophobic counterions. The DdilH values were neg. (exothermic) and decreased as the no. of C atoms increased. The non-electrostatic terms DdilHn of were evaluated by using the electrostatic terms of DdilH obtained from Manning's theory. The DdilHn values decreased, i.e., their exothermic tendencies increased, as the no.In this experiment, several chemicals are used like 83799-51-3 and 39455-18-0 of C atoms of R4N+ increased, and the rate of decrease of the R4NPAA was more than that of the R4NChSA. These results are discussed in relation to the increase of the hydrated water structure around R4N+ on diln. .