Films protein

Surfaces can be active in inducing blood clotting, and there is much current searching for thromboresistant synthetic materials for use in surgical repair of blood vessels (see Ref. 111). It may be important that a protective protein film be strongly adsorbed [112]. The role of water structure in cell-wall interactions may be quite important as well [113]. 

The structure of whipped cream is quite complex. A coating of milk protein surrounds small globules of milk fat containing both solid and liquid fats. These globules stack into chains and nets around air bubbles. The air bubbles are also formed from the milk proteins, which create a thin membrane around the air pockets. The three-dimensional network of joined fat globules and protein films stabilizes the foam, keeping the whipped cream stiff. 

A large number of potential applications for organized protein monolayers have recently motivated considerable research activity in this field (Boussaad et al. 1998, Kiselyova et al. 1999). Construction of specific interaction-directed, self-assembled protein films has been performed at the air-water interface. The Langmuir-Blodgett (LB) technique has been extensively used to order and immobilize natural proteins on solid surfaces (Tronin et... 

Enhanced thermal stability enlarges the areas of application of protein films. In particular it might be possible to improve the yield of reactors in biotechnological processes based on enzymatic catalysis, by increasing the temperature of the reaction and using enzymes deposited by the LB technique. Nevertheless, a major technical difficulty is that enzyme films must be deposited on suitable supports, such as small spheres, in order to increase the number of enzyme molecules involved in the process, thus providing a better performance of the reactor. An increased surface-to-volume ratio in the case of spheres will increase the number of enzyme molecules in a fixed reactor volume. Moreover, since the major part of known enzymatic reactions is carried out in liquid phase, protein molecules must be attached chemically to the sphere surface in order to prevent their detachment during operation. 

The deposition procedure described earlier allows one to obtain protein films chemically bound to the activated surface of spherical glass particles. Subsequent compression of preformed protein monolayer with these particles permitted to coverage of the particle area that initially has not come in contact with the monolayer, as schematically shown in Figure 14. Even if such a procedure does not initially result in deposition of strictly one monolayer, this fact does not seem to be critical, because only the monolayer chemically attached to the surface remains after washing. 

Thirdly, a stable icing foam requires a tendency for the surface of the extended protein film to solidify, thereby giving structure and permanence to the foam. Egg albumen is a hydrophilic (water-loving) colloid, for it is readily soluble in water. However, when subjected to heat, egg albumen becomes insoluble in water or is said to be hydrophobic (water-hating). Through this phenomenon of changing solubility, egg whites make very stable foams if used at sufficient concentration. 

The large size of redox enzymes means that diffusion to an electrode surface will be prohibitively slow, and, for enzyme in solution, an electrochemical response is usually only observed if small, soluble electron transfer mediator molecules are added. In this chapter, discussion is limited to examples in which the enzyme of interest is attached to the electrode surface. Electrochemical experiments on enzymes can be very simple, involving direct adsorption of the protein onto a carbon or modified metal surface from dilute solution. Protein film voltammetry, a method in which a film of enzyme in direct... 

Barker CD, Reda T, Hirst J. 2007. The flavoprotein suhcomplex of complex I (NADH ubiquinone oxidoreductase) from bovine heart mitochondria Insights into the mechanisms of NADH oxidation and NAD reduction from protein film voltammetry. Biochemistry 46 3454-3464. 

Heering HA, Wiertz FGM, Dekker C, de Vries S. 2004. Direct immobilization of native yeast Iso-1 cytochrome c on bare gold Fast electron relay to redox enzymes and zeptomole protein-film voltammetry. J Am Chem Soc 126 11103-11112. 

Leger C, Elliott SJ, Hoke KR, Jeuken LJC, Jones AK, Armstrong FA. 2003. Enzyme electrokinetics Using protein film voltammetry to investigate redox enzymes and their mechanisms. Biochemistry 42 8653-8662. 

Formation of multicomponent protein films by Layer-By-Layer (LBL) or Langmuir-Blodgett adsorption have been developed for a broad range of applications... 

J. B. Lhoest, M. S. Wagner, C. D. Tidwell and D. G. Castner, Characterization of adsorbed protein films by time of flight secondary ion mass spectrometry, Journal of Biomedical Materials Research, 57, 432 440 (2001). 

L. Shen and N.F. Hu, Heme protein films with polyamidoamine dendrimer direct electrochemistry and electrocatalysis. BBA-Bioenergetics 1608, 23—33 (2004). 

Park SK, Rhee CO, Bae DH and Hettiarachchy NS. 2001. Mechanical properties and water-vapor permeability of soy-protein films affected by calcium salts and glucono-D-lactone. J Agric Food Chem 49(5) 2308-2312. 

Studies of protein film electrocatalysis have also been illuminating. For example, succinate dehydrogenase displays an unusual optimal potential for activity. The enzyme contains four redox sites a flavin, a... 

We have observed that such proteins as CaM and bovine serum albumin (BSA) can be developed at the air-water interface to form monolayer protein films. In previous works, the developed BSA monolayer was stabilized by cross-linking with a bifunctional reagent immediately after the preparation of protein monolayer. The BSA thin film thus prepared can be employed as a passive material, e.g., an ultrathin protein film for a matrix of enzyme-linked immunosorvent assays. 

Chen, X., Knight, D. P., Shao, Z. Z., and Vollrath, F. (2002). Conformation transition in silk protein films monitored by time-resolved Fourier transform infrared spectroscopy Effect of potassium ions on Nephila spidroin films. Biochemistry 41, 14944-14950. 

It must be taken into account that the redox potential of protein films slightly depend on the nature of the surfactants themselves and... 

B.S. Murray, B. Cattin, E. Schuler, and Z.O. Sonmez Response of Adsorbed Protein Films to Rapid Expansion. Langmuir 18, 9476 (2002). 

Adsorbed protein films, cluster reactivities, 38 144-159 clusters... 

Some crystals may remain in the cells, which act as vessels, and form textures consisting of crystals and protein films in other cases, crystals protrude from the cell, where they may connect with others formed in neighboring cells or discharge from the cell and connect with other crystals to form higher-order textures, such as an exo-skeleton. 

As summarized in Table 14.1, teeth, bones, shells, etc. are indispensable components, consisting of inorganic mineral crystals and protein film, with sizes, morphologies, and textures suitable to fulfil the function of the particular organs involved. In this section we will look at hydroxyapatite, aragonite and calcite (two polymorphs of CaCO ), and magnetite in greater detail. 

Rodriguez Patino, J.M., Rodriguez Nino, M.R., Sanchez, C.C. (2007). Physico-chemical properties of surfactant and protein films. Current Opinion in Colloid and Interface Science, 12, 187-195. 

The second phase is a regime in which the protein film is no longer compressible, but it compensates for the decrease in surface area through a corresponding increase in film thickness. This causes a buckling of the protein layer, including dissociation of at least some of the protein from the air-water interface, but not from the protein film itself. 

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