Detail of "2280-01-5"

Reference

Stabilization of human albumin by caprylate and acetyltryptophanate

Stabilization of human albumin by caprylate and acetyltryptophanate. Yu, M. W.; Finlayson, J. S. (Div. Blood and Blood Prod., Natl. Cent. Drugs and Biol., Bethesda, MD, USA). Vox Sang., 47(1), 28-40 (English) 1984. CODEN: VOSAAD. ISSN: 0042-9007. DOCUMENT TYPE: Journal CA Section: 63 (Pharmaceuticals) The thermal stabilization of human albumin by Na caprylate (CA) [1984-06-1] and N-acetyl-DL-tryptophan (AT) [87-32-1] was studied by monitoring the formation of albumin polymer (defined as species larger than dimer) on the basis of its mol. size as well as its characteristic migration as a-globulin. Heating 5% protein solns. of purified albumin monomer, Cohn fractions IV and V at 60° in 0.1 M Na3PO4 or 145 mM NaCl (pH 7.0), established the following order of stabilizer effectiveness: 4 mM CA + 4 mM AT u 4 mM CA > 8 mM AT 3 2 mM CA > 4 mM AT. However, albumin was more thermally stable in the chloride medium. Raising the CA concn. above 4 mM provided little addnl. stabilization. D-AT [2280-01-5] and L-AT [1218-34-4] were equally effective, but 16 mM AT wa needed to equal the effect of 4 mM CA. L-Tryptophan [73-22-3] exerted only slight stabilization, even at 32 mM; D-tryptophan [153-94-6] was even less effective. The albumin polymer level increased progressively with time at 60 °C in 2 mM CA or 4 mM AT, whereas in 4 mM CA it reached a plateau in 4-6 h. Acetone drying of albumin-rich fractions removed nearly all endogenous fatty acid, rendering the protein thermally labile unless sufficient exogenous stabilizer(s) was added. Even in the presence of 145 mM NaCl, and 4 mM CA + 4 mM AT or 4 mM CA, the stabilizing effect of endogenous fatty acid was still detectable.

Thermal stability of human albumin measured by differential scanning calorimetry

Thermal stability of human albumin measured by differential scanning calorimetry. II. Effects of isomers of N-acetyltryptophanate and tryptophanate, pH, reheating, and dimerization. Ross, P. D.; Finlayson, J. S.; Shrake, A. (Off. Biol., Natl. Inst. Arthritis, Diabetes, Dig. Kidney Dis., Bethesda, MD, USA). Vox Sang., 47(1), 19-27 (English) 1984. CODEN: VOSAAD. ISSN: 0042-9007. DOCUMENT TYPE: Journal CA Section: 63 (Pharmaceuticals) The thermal stability of undefatted human albumin prepns. at 5% concn. and neutral pH in 145 mM Na+ was investigated by DSC . At 30 and 4 mM N-acetyltryptophan [87-32-1], the thermogram for previously unheated albumin monomer is independent of the stereochem. of this ligand; thus, the affinity of the protein must be the same for the L- [1218-34-4] and D- [2280-01-5] isomers in the temp. range of thermal denaturation (62-86°). L-Tryptophan [73-22-3] (26 mM) bestows a slight increase in stability on previously unheated monomer, whereas 27 mM D-tryptophan [153-94-6] has no effect, a result consistent with the reported weaker binding of the D-isomer. Previously unheated albumin monomer shows slightly greater thermal stability at pH 6.4 than at pH 7.4. The tracing of differential heat capacity vs. temp. (thermogram) for monomer from once heated albumin, i.e. once processed and once heated normal serum albumin (NSA), is almost identical to that for previously unheated monomer. Monomer prepd. from outdated, multiply reprocessed, multiply reheated NSA (old monomer) has the same corresponding denaturation temps. as previously unheated monomer; the corresponding dimer (old dimer) is slightly less stable. Thermograms for old monomer and old dimer, like those for previously unheated monomer, comprise 2 denaturation peaks (endotherms). Their endotherms, however, are very broad, reflecting the great heterogeneity of the old proteins. The thermogram for old monomer remains broad even in the presence of N-acetyltryptophan and/or Na caprylate [1984-06-1]. Older dimer does not dissoc. when undergoing thermal denaturation.