Learning to Review Literature

Thermodynamic nonideality in macromolecular solutions

“…for which the total accessible volume (V,) and void volume ( Vo) of the column were taken as the respective elution volumes of Co3+ ion and a blue dextran 2000 sample that had been subjected to prior zonal gel chromatography on Sepharose 6B to remove any partitioning material. These partition coefficients, obtained at a series of molar protein concentrations, [A], were then used in conjunction with the expression [6, 241 c A = @i exp{ wAALA] (l -eA)} (2) to obtain the second virial coefficient, a,,, as the slope of a plot of In oA versus [A] (1 -0,): a1 is the limiting value of the partition coefficient as [A] + 0. For the conversion of protein concentrations from a mass to a molar basis the following molar masses were used: ovalbumin 45 kg/mol [39], bovine serum albumin 66 kg/mol [36], ribonuclease 13.7 kg/mol [33] and catalase 250 kg/mol [40].…”

“…The effect of protein concentration on the partition coefficients of ovalbumin (0), ribonuclease (O), bovine serum albumin (m) and catalase (0) in frontal gel chromatography on Fractogel TSK HW55 are summarized in Fig. 1, where the results are plotted in the format suggested by the logarithmic form of Eqn (2). Slopes of these essentially linear plots were therefore obtained by least-squares calculations to yield the second virial coefficients (mAA) recorded as the first four entries in the column for this parameter in Table 1.…”

Human peripheral blood leukocytes transplanted on CB17 scid‐scid mice are transferred to their offspring

“…Mice with >50ng/ml Ig levels were termed leaky; mice with <50 ng/ml were used as scid. This low value, which is 1000-fold lower than that originally defined by Bosma et al [4], was found necessary for transfer experiments.…”

Thermodynamic nonideality in enzyme catalysis

“…The experimentally observed insensitivity of the Michaelis constant for pyruvatc to albumin concentration is in keeping with theoretical prediction, but incorporation of the measured extent of maximal velocity enhancement into the kinetic model leads to a predicted volume for the fully saturated transition-state complex that is far too small to be experimentallyfeasible. A more complex mechanistic model involving additional isomerizations of enzyme-substrate species is thus required to achieve quantitative description of the albumin effect solely in terms of thermodynamic nonideality.The possible consequences of thermodynamic nonideality arising from the space-filling effects of inert solutes on enzyme systems were brought into prominence by the theoretical demonstration [I], in response to an experimental observation [2], that inclusion of solutes such as poly(ethy1ene glycol) could displace a self-association equilibrium from a point of nondetectability of polymer to a situation in which polymer is essentially the sole species present. Qualitatively similar effecls should also occur with enzymes undergoing substrate-induced conformational changes of sufficient magnitude to result in altered molecular dimensions (size/asymmetry) of the enzymc [3].…”

“…The possible consequences of thermodynamic nonideality arising from the space-filling effects of inert solutes on enzyme systems were brought into prominence by the theoretical demonstration [I], in response to an experimental observation [2], that inclusion of solutes such as poly(ethy1ene glycol) could displace a self-association equilibrium from a point of nondetectability of polymer to a situation in which polymer is essentially the sole species present. Qualitatively similar effecls should also occur with enzymes undergoing substrate-induced conformational changes of sufficient magnitude to result in altered molecular dimensions (size/asymmetry) of the enzymc [3].…”