Bulk proteins

Adsorption isotherms of albumin on glass were established at bulk BSA concentrations from 0.1 to 5% (w/v) in PBS. The cleaned glass slides were immersed in the bulk protein solution for 30 min at 23°C and then rinsed by dilution/displacement. 

Limiting cases of the general convective-diffusion equation are often helpful. If the time dependence is ignored, i.e., 5C/0t = 0 (for example, at low bulk protein concentration, at long times, and/or when the rate of adsorption is much greater than the transport to the surface), then we have... 

Specific modifications of proteins result from adding a selected reagent to the pure protein or crude protein-rich material. This may be done in the course of a fundamental study in protein chemistry or as a step in the production of a bulk protein product for practical purposes. The same chemical modification can be useful in both processes. For example, enzyme chemists use charge-changing modifications to dissociate oligomeric proteins to their monomer components, while the same modifications are proposed as a means of solubilizing yeast proteins to permit their extraction for use in foods (11). This chapter is concerned mainly with the many types of intended modifications. 

Load protein solution, (allow to adsorb, 1-5 min.) Total Adsorbed bulk protein, buffer... 

It has been shown here that ATR-FTIR spectra of proteins in solution can be collected and used successfully for secondary structural analysis. Relatively accurate bulk protein spectra can be obtained by subtracting the spectrum of protein irreversibly adsorbed to the surface of an IRE. 

The interiors of proteins are more densely packed than liquids [181], and so the participation of the atoms of the protein surrounding the reactive system in an enzyme-catalysed reaction is likely to be at least as important as for a reaction in solution. There is experimental evidence which indicates that protein dynamics may modulate barriers to reaction in enzymes [10,11]. Ultimately, therefore, the effects of the dynamics of the bulk protein and solvent should be included in calculations on enzyme-catalysed reactions. Dynamic effects in enzyme reactions have been studied in empirical valence bond simulations Neria and Karplus [180] calculated a transmission coefficient of 0.4 for proton transfer in triosephosphate isomerase, a value fairly close to unity, and representing a small dynamical correction. Warshel has argued, based on EVB simulations of reactions in enzymes and in solution, that dynamical effects are similar in both, and therefore that they do not contribute to catalysis [39]. 

Ricin may inhibit the synthesis of specific proteins to different extents in a myeloma cell line, for example, the synthesis of IgA is inhibited more rapidly than is bulk protein synthesis (Ko and Kaji, 1975). There is currently insufficient experimental evidence, however, to conclude that preferential inhibition of the synthesis of specific proteins significantly influences ricin cytotoxicity in vivo. 

The regulation of total- or bulk-protein synthesis is independent of mRNA levels and the rate-limiting factors, in principle, can be any of the components of the protein synthetic machinery. Therefore, all three steps of initiation, elongation, and termination are targets in the regulation of protein synthesis. 

We note that the reaction coordinate is coupled to an infinite bath of harmonic oscillators, which represent the bulk protein, and to a protein promoting vibration. For each mathematical implementation, we here choose the zero of promoting vibration coupling to be in the well rather than at the barrier top, but this is arbitrary. We point out that we can tune this model to allow for both sequential and concerted hydrogen-electron transfer. Sequential transfer is found with a very high transfer rate, and concerted with a lower one. 

The correction for bulk protein concentrations other than 1.0 mg/mL is represented by CB. Surface concentrations T ( xg/cm2) were calculated on the basis of Equation 4 and presented as a function of time or bulk concentration CB for adsorption-desorption dynamics or adsorption isotherms, respectively. 

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