Molar mass protein

Metallothioneins (MT), low molar mass proteins, have been studied electrochemi-cally alone and in the presence of Cd(II) and Zn(II) ions [110-115]. The electrochemical behavior of zinc MTs from rabbit liver, with respect to solution pH, as well as the influence of the addition of zinc [116] and also zinc MT from rat liver, was investigated [117] using electroanalytical techniques. Studies of complexing properties of the alpha-MT with Zn(II) were carried out using differential pulse po-larography [118]. 

The porous nature of the fibers allows for exchange of nutrients and metabolites. Low-molar-mass molecules, such as glucose and ammonia, can move freely through the pores of the fibers, at a rate that is controlled just by the pressure gradients generated by the medium recirculation pump. High-molar-mass proteins, which can be produced by the cells or added as nutritional supplements to the extracapillary space, are not able to permeate the membrane fibers and are retained in the cell bed in the ECS. 

Renal tubular cells Endothelia Low molar mass proteins (cationic)... 

Low molar mass proteins Low molar mass proteins, such as lysozyme, have been recently suggested as a potential carrier for targeting drugs to the kidney (311). The... 

The lipoproteins are dissolved and the ribosomes are obtained when microsomes are treated with deoxycholic acid. Ribosomes are compounds consisting of equal mass fractions of nucleic acids and proteins they are nucleoproteins. The relatively low-molar-mass proteins are bound to the rod-shaped high-molar-mass helical nucleic acids via Mg ions. The molar mass of these monomolecular nucleoproteins can be several millions. 

Proteases effect the hydrolysis of peptide bonds. Some may also cause the scission of ester bonds or transpeptidization (exchange of peptide bonds). Some are produced from high-molar-mass proteins by the elimination of amino acids. These high-molar mass proteins are called precursors or zymogens. 

Therefore, enzymatic degradation is a surface phenomenon, in contrast to pure hydrolysis. In fact, enzymes are high molar mass proteins which are not able to penetrate a solid polymeric material. Instead, enzymes can eventually adsorb on a polymer surface. Enzymatic degradation thus consists in two steps (1) adsorption of enzymes on the surface of a polymer matrix through their binding domain, (2) ester bond cleavage due to the effect of the catalytic domain of the enzyme. In the case of PLA-based materials, the amorphous parts and l-LA units are preferentially degraded by proteinase K. 

Unlike platinum, which catalyzes a wide variety of reactions, the catalytic action of high-molar-mass proteins known as enzymes is very specific. For example, in the digestion of milk, lactose, a more complex sugar, breaks down into two simpler ones, glucose and galactose. This occurs in the presence of... 

Entropy change, AS, is the difference in entropy between two states of a system. An enzyme is a high molar mass protein that catalyzes biological reactions. 

A biochemist isolates a new protein and determines its molar mass by osmotic pressure measurements. A 50.0-mL solution is prepared by dissolving 225 mg of the protein in water. The solution has an osmotic pressure of 4.18 mm Hg at 25°C. What is the molar mass of the new protein ... 

Many reactions that take place slowly under ordinary conditions occur readily in living organisms in the presence of catalysts called enzymes. Enzymes are protein molecules of high molar mass. An example of an enzyme-catalyzed reaction is the decomposition of hydrogen peroxide ... 

A 1.00-mg sample of a pure protein yielded on hydrolysis 0.0165 mg of leucine and 0.0248 mg of isoleucine. What is the minimum possible molar mass of the protein (MM leucine = MM isoleucine = 131 g/mol)... 

A sample consisting of 155 mg of a purified protein is dissolved in 10.0 mL of ethanol. This solution is placed in a device for measuring osmotic pressure and rises to a final height of 32.5 cm above the level of pure ethanol. The experiment is performed at 1.00 atm and 298 K. The density of ethanol at 298 K is 0.79 g-cm "3. What is the molar mass of the protein Assume that the density of the solution is the same as that of pure ethanol. See Exercise 8.95. 

In nature, there are 20 amino acids available for incorporation into the protein chain. They are arranged in a specific and characteristic sequence along the molecule. This sequence is generally referred to as the primary structure of the protein. Also part of the primary structure is the relative molar mass of the macromolecule. 

Overall, as is apparent from this description, light scattering is a difficult, time-consuming technique, despite its great importance. Despite this, the technique has been used to measure relative molar masses as low as that of sucrose and as high as those of proteins, and has been found to have a useful range for polymers of relative molar masses between ten thousand and ten million. 

C03-0023. Twenty different amino acids are the essential building blocks of proteins. Calculate the molar masses of these three. 

C12-0018. When 7.50 mg of a protein is dissolved in water to give 10.00 mL of solution, the osmotic pressure is found to be 1.66 torr at 21°C. Determine the molar mass of the protein. 

C12-0019. A water-soluble protein molecule has a molar mass of 985 g/mol. Calculate the freezing point... 

Both Reynolds and Karim worked at neutral pH, with denatured proteins, and with reduced disulfide bonds. Under these conditions, proteins are in a random coil conformation (Mattice et al., 1976), so that their hydrodynamic radius is monotoni-cally related to their molar mass. Takagi et al. (1975) reported that the binding isotherm of SDS to proteins strongly depends upon the method of denaturing disulfide bonds. Presumably, protein-SDS complexes are not fully unfolded when disulfide bonds are left intact, which breaks the relationship between molar mass and hydrodynamic... 

In contrast to biological macromolecules such as proteins, synthetic polymers are, in general, polydisperse. Their molar masses, which show a broad distribution of... 

In addition to the determination of molar mass distributions and various molar mass averages there are many experiments, requiring sometimes sophisticated data evaluation, that can be carried out with an analytical ultracentrifuge. Examples are the analysis of association, the analysis of heterogeneity, the observation of chemical reactions, and protein characterization, to mention only a few. A detailed discussion is beyond the scope of this article, but there is excellent literature available [77-79,81,87-89]... 

Proteins and peptides are most often seen in the mass spectra as pseudomolecular ions, that is, molecules with attached charge-carrying protons (in the negative-ion mode, proteins and peptides lose protons and thus acquire a negative net charge). This additional proton has to be taken into consideration in order to predict correctly the m/z value at which the peptide of interest will be seen in a mass spectrum. For example, a peptide whose molecular weight (MW) (or molar mass) is equal to 2000 Da, when singly ionized, will be detected at 2001 m/z (for simplification, we assume the mass of proton as equal to 1) ... 

In this equation, u is the osmotic pressure in atmospheres, n is the number of moles of solute, R is the ideal gas constant (0.0821 Latm/K mol), T is the Kelvin temperature, V is the volume of the solution and i is the van t Hoff factor. If one knows the moles of solute and the volume in liters, n/V may be replaced by the molarity, M. It is possible to calculate the molar mass of a solute from osmotic pressure measurements. This is especially useful in the determination of the molar mass of large molecules such as proteins. 

A solution prepared by dissolving 6.95 x 10 1 3 g of protein in 0.0300 L of water has an osmotic pressure of 0.195 torr at 25°C. Assuming the protein is a nonelectrolyte, determine the molar mass of the gene fragment. 

In this form, van t Hoff s law of osmotic pressure is also used to determine the molar masses of biological and synthetic macromolecules. When the osmotic pressure is measured for a solution of macromolecules that contains more than one species of macromolecule (for example, a synthetic pol5mer with a distribution of molar masses or a protein molecule that undergoes association or dissociation), the osmotic pressures of the various solute species II, are additive. That is, in sufficiently dilute solution... 

A low or high molar mass stabilizing component whenever the polymer matrix of choice does not exert a stabilizing effect on the trapped protein drug. 

The important feature of many polymers is simultaneous presence of distributions in two and several molecular characteristics. Polymers exhibiting multiple distributions are called the complex polymers or complex polymer systems. A detailed discussion of molecular characteristics of polymers and their average values and distributions can be found in numerous monographs and reviews, for example [34,35]. For the present purpose, it is important to repeat that all synthetic polymers and also polysaccharides are polydisperse in their nature. Only mother nature is able to produce macromolecules, for example many proteins, with uniform molar mass. The latter are often improperly called monodisperse(d) polymers. 

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