TAPSO

Abstract: The generation of fluorescence and 3-deoxyglucosone (3DG), browning, polymerization, and impairment of the amino acid residues of lysozyme incubated with glucose were investigated at 37 degrees C and 50 degrees C at pH 7.4 in a phosphate or TAPSO buffer under aerobic and non-aerobic conditions with or without DETAPAC as a chelating reagent. Browning, the generation of fluorescence, and polymerization were accelerated under the non-aerobic, compared to aerobic, conditions. Moreover, the formation of 3DG was also significantly increased under non-aerobic conditions. The incubation of both reaction systems resulted in noticeable losses of arginine and lysine residues. DETAPAC significantly inhibited the advanced Maillard reaction under both aerobic and non-aerobic conditions. However, DETAPAC had no effect on the impairment of lysine and arginine residues. The generation of fluorescence, browning and polymerization of lysozyme in the TAPSO buffer were markedly inhibited under both aerobic and non-aerobic conditions. These observations suggest that transition metals in the phosphate buffer may have accelerated the formation of Amadori compounds via Schiff's base. In addition, under non-aerobic conditions, the formation of advanced glycation end products from 3DG via Amadori compounds is presumed to be the major pathway, because the formation of N epsilon-(carboxymethyl)lysine, glyoxal, and glucosone was accelerated by an oxidative reaction catalyzed with transition metal ions. These presumptions are supported by the results from a lysozyme-3DG reaction system.

Abstract: In a situation which is far from ideal, many buffers have been found to be quite reactive, besides maintaining their stable pH values. On the basis of apparent transfer free energies (ΔG(tr)'), through solubility measurements the interactions of zwitterionic glycine peptides: glycine (Gly), diglycine (Gly(2)), triglycine (Gly(3)), and tetraglycine (Gly(4)), with several common neutral pH, amine-based buffers have been studied. The biological buffers studied in this work, including TRIS, TES, TAPS, TAPSO, and TABS are structurally related and all contain TRIS groups. These buffers have pK(a) values ranging from 7.5-9.0, which allow them to be used in biological, biochemical or environmental studies. We observed negative values of ΔG(tr)' for Gly(3) and Gly(4) from water to buffer, indicating that the interactions are favorable. However, the ΔG(tr)' values are positive for Gly and Gly(2), revealing unfavorable interactions, which except for the latter in TRIS buffer are negative. The surprising result in our data is the unexpected extraordinarily high favorable interactions between TRIS buffer and peptides (in comparison with the effect of the most common denaturants, urea and guanidine hydrochloride). The transfer free energies (ΔG(tr)') of the peptide backbone unit (-CH(2)C=O-NH-) contributions have been estimated from ΔG(tr)' values. We have also investigated the interactions of TRIS buffer with Bovine Serum Albumin (BSA), as a globular protein, using dynamic light scattering (DLS), zeta potential, UV-Visible absorption, fluorescence and Raman spectroscopy measurements. The results indicated that TRIS buffer stabilized the BSA molecules.

Abstract: Potentiometric equilibrium measurements have been performed at (25.0 ± 0.1) °C and ionic strength I = 0.1 mol dm-3 (KNO3) for the interaction of glycine (aminoethanoic acid), serine (2-amino-3-hydroxypropanoic acid), methionine (2-amino-4-(methylthio)butanoic acid), aspartic acid (aminobutanedioic acid), glutamic acid (2-aminopropanedioic acid), and histidine (α-amino-1H-imidazole-4-propanoic acid) and Cu(II), Co(II), Ni(II), Mn(II), and Zn(II) with the biologically important secondary ligand zwitterionic buffers β-hydroxy-4-morpholinepropanesulfonic acid (MOPSO), 4-morpholinepropanesulfonic acid (MOPS), 3-[bis(2-hydroxyethyl)amino]-2-hydroxy-1-propanesulfonic acid (DIPSO), and 3-[N-tris(hydroxymethyl)methyl)amino]-2-hydroxypropanesulfonic acid (TAPSO) in 1:1:1 and 1:1:2 ratios, and the formation of various 1:1:1 ternary complexes and 1:1:2 quaternary complex species was inferred from the potentiometric pH titration curves. Initial estimates of the formation constants of the resulting species and the acid...

Abstract: A new range of Good’s buffer ionic liquids (GB-ILs), displaying simultaneously the properties of ionic liquids and Good’s buffers, were synthesized by a combination of Good’s buffer anions (MOPSO, BES, TAPSO, and CAPSO) and tetrabutylammonium, tetrabutylphosphonium, and cholinium cations via an acid–base neutralization reaction. The activity and stability of a lipolytic enzyme from Pseudomonas cepacia in aqueous solutions of these buffers were evaluated, and the results show their advantage as media for enzymatic reactions when compared to conventional phosphate buffers. Moreover aqueous biphasic systems (ABS) composed by these GB-ILs and potassium citrate were investigated and shown to be highly effective and selective for the partitioning of the lipolytic enzyme into the GB-IL-rich phase. The results allow for the development of an efficient and biocompatible process combining the self-buffering and enzyme-stabilizing properties of the GB-ILs in the reaction step, with the advantages of GB-ILs as extrac...