Interaction of cytosolic apo-aspartate aminotransferase with AMP has been studied under equilibrium conditions; e.g., equilibrium dialysis and spectrophotometric titration. Results show that a 1:1 stoichiometric complex AMP-apo-aspartate aminotransferase monomer is formed. The calculated dissociation constants with the two different experimental techniques are 40.4 x 10(-6) M-1 and 31.4 x 10(-6...

Basicity constants for a series of 3,7-diazabicyclo[3.3.1]nonane derivatives in acetonitrile with a variation over 13 orders of magnitude have been determined using a spectrophotometric titration technique. An excellent correlation between basicity and calculated proton affinities obtained at PCM-B3LYP/6-31+G(d)//B3LYP/6-31G(d) level was found. The results are discussed in terms of substituent ...

The ionization of tyrosine residues in human lysozyme was investigated by measurement of spectral changes at pH values between 8.74 and 12.75. Below pH 11.70, at ionic strength 0.10, the titration curve is fully reversible. An average of 4 tyrosine eq per mole are ionized at this PH. At pH values higher than 11.70, the spectra are time-dependent. Reversal from any pH above 11.7, after 12 to 30 ...

Much useful information of a quantitative nature can be obtained with redox-active proteins by anaerobic titration with reducing substrates or chemical reductants such as sodium dithionite. We have used successfully for many years anaerobic spectrophotometer cells equipped with either two or four side arms from which known amounts of titrant can be added (1). This technique gives only a limited...

2,10-Disubstituted phenothiazines are the best drugs in psychiatry. Several methods for their analysis have been reported in the literature. The official methods are based on non-aqueous titration or spectrophotometry. Various oxidizing agents have been used for the spectrophotometric determination of 2,10-disubstituted phenothiazines, e.g. Ce(SO4)2, NH4VO3, K2S208, KIO4, KIO3, KBrO3, FeCl3, Na...

We employed quantitative NMR spectroscopy and spectrophotometric absorbance titration to study a quantum dot X-type ligand exchange reaction. We find that the exchange is highly cooperative, where at low extents of exchange the change in free energy of the reaction, ΔGXC, is ∼11 kJ mol-1 while at higher extents of exchange ΔGXC saturates to ∼-4 kJ mol-1. A modified Fowler binding isotherm is de...

the interaction of bovine serum albumin ( bsa) and egg albumin with water solublephthalocyanine, cobalt (ιι) 4, 4′ , 4′′, 4′′′- tetrasulfophthalocyanine ( cotspc) , has been studiedby the uv- vis method at ph 7.0 and five different temperatures 20, 25, 30, 35 and 40°c. theformation constants have been elucidated by using spectrophotometric titration and computersquad program data refinement. th...

An automated analyzer was developed to achieve fast, precise, and accurate measurements of seawater total alkalinity (AT) based on single-point titration and spectrophotometric pH detection. The single-point titration was carried out in a circulating loop, which allowed the titrant (hydrochloric acid and bromocresol green solution) and a seawater sample to mix at a constant volume ratio. The di...