Protein density

Here Xprotein is real space coordinate within the protein region, H(p(x)) is the expected, non-Gaussian histogram of the electron density and H°i (p(x)) is the observed histogram of protein density which may or may not have phase errors. 

Also, since the 3-D NPH could be formed on specific limited areas of a substrate, a protein array with high protein density can be produced without crosscontamination among neighboring spots and without overflow. 

Lipoprotein Percent Protein Density (g/mL) Primary Function... 

The net charge on albumin appears to be more significant than the nature of the substrate when considering how much protein initially binds to the aqueous/solid interface. More protein adsorbed onto copper, nickel, and germanium substrates at pH 4.8, where albumin has no net surface charge, than at pH 4.0 or pH 7.4. Since no charge effects exist between the macromolecules adsorbed on the surface, high protein densities at the aqueous/solid interface would be expected. Copper and nickel appeared to accumulate the same quantities of albumin independent of the pH studied. 

Fischer, H., Polikarpov, I., and Craievich, A. F. (2004). Average protein density is a molecular-weight-dependent function. Protein Sci. 13, 2825—2828. 

Theoretically, inverse agonists may be useful agents for the treatment of disease symptoms caused by constitutive receptor activity. Covalent modifications of the receptor protein, pathological increase in receptor or G protein densities, or inherited or somatic point mutations may lead to increased constitutive receptor activity. For example, certain inherited point mutations in rhodopsin have been shown to cause retinitis pigmentosa. The involvement of inherited, constitutively activating receptor point mutations has also been demonstrated in certain forms of hyperthyroidism, in male precocious puberty, and in Jansen-type metaphyseal chondrodysplasia [8]. Constitutive G protein activity may also be an important factor in autoimmune diseases [9]. 

The CAT model was further modified to include pH-dependent solubility, dis-solution/precipitation, absorption in the stomach or colon, first-pass metabolism in gut or liver, and degradation in the lumen. Physiological and biochemical factors such as changes in absorption surface area, transporter, and efflux protein densities have also been incorporated. This advanced version of CAT, called ACAT [176], has been formulated in a commercially available simulation software product under the trademark name GastroPlus . A set of differential equations, which is solved by numerical integration, is used to describe the various drug processes of ACAT as depicted in Figure 6.4. 

Calculate the average density of a membrane composed of 30 percent (by weight) protein (density, 1.33gem--1) and 70 percent by weight phosphoglyceride (density, 0.92gem-3). 

Adhesion of different immune cells to one another or to epithelial cells has also been studied using planar bilayer models. For example, lymphocyte function-associated protein-1 (LFA-1) promotes cell adhesion in inflammation [i.e., a reaction that can be mimicked by binding to purified ICAM-1 in supported membranes (70)]. Similarly, purified LFA-3 reconstituted into supported bilayers mediates efficient CD2-dependent adhesion and differentiation of lymphoblasts (71). This work was followed by a study in which transmembrane domain-anchored and GPl-anchored isoforms of LFA-3 were compared (72). Because this research occurred before the introduction of polymer cushions and because the bilayers were formed by the simple vesicle fusion technique, the transmembrane domain isoform was immobile, whereas the GPl isoform was partially mobile. By comparing results with these two isoforms at different protein densities in the supported bilayer, the authors showed that diffusible proteins at a sufficient minimal density in the supported membrane were required to form strong cell adhesion contacts in this system. 

Beans and peas, which are legumes, are good sources of protein. Their protein densities are quite similar to that of eggs. The grains, including rice, wheat, and... 

The concerns of the nutritionist regarding protein extend well beyond protein content and protein density. A major concern in human and anima nutrition is the quality of the protein. The term protein quality refers to the ability of a particular protein to provide a balanced pattern of indispensable amino acids. A hi -quality protein contains high concentrations of the indispensable amino acids. A low-quality protein is deficient or lacking in one or more of these amino acids. Although beans and eggs are similar, as far as protein density is concerned, the quality of egg protein is considerably better than that of protein from beans. 

TABLE 8.1 Protein Content and Protein Density of Various Foods"... 

Food Protein content (g/100 g food) Energy content (kJ/lOOgfood) "Protein density" (g/1000 kj energy)... 

The importance of restricting the protein density on the supporting medium has been stressed (02). Yet even at low concentrations, the relationship between several dyes and protein is consistently nonlinear whether... 

---