Protein like lysozyme

The formation of spanning H-bonded water networks on the surface of biomolecules has been connected with the widely accepted view that a certain amount of hydration water is necessary for the dynamics and function of proteins. Its percolative nature had been suggested first by Careri et al. (59) on the basis of proton conductivity measurements on lysozyme this hypothesis was later supported by extensive computer simulations on the hydration of proteins like lysozyme and SNase, elastine like peptides, and DNA fragments (53). The extremely interesting... 

Native proteins are expected to remain folded when sprayed from neutral aqueous solutions. Under these conditions the folded (nondenatured) proteins lead to mass spectra consisting of a compact series of peaks that correspond to the molecular mass of the protein charged by a narrow range of H ions when the positive ion mode is used. Thus, a small protein-like lysozyme (molecular mass... 

Squaraine dyes 10b, 39a, 39b, 41a, 41c, 41d, and 41e were used to measure different proteins such as BSA, HSA, ovalbumin, avidin from hen egg white, lysozyme, and trypsin (Fig. 12) [58]. It is difficult to predict correlations between the dyes structures and the affinity or sensitivity of the dyes for different proteins. All squaraine probes exhibit considerable fluorescence increases in the presence of BSA. Dicyanomethylene-squaraine 41c is the brightest fluorescent probe and demonstrates the most pronounced intensity increase (up to 190 times) in presence of BSA. At the same time, the fluorescent response of the dyes 10b, 39a, 39b, 41a, 41c, 41d, and 41e in presence of other albumins (HSA and ovalbumin) is, in general, significantly lower (intensity increases up to 24 times). Dicyanomethylene-squaraine 41a and amino-squaraines 39a and 39b are the most sensitive probes for ovalbumin. Dyes 41d, 10b, and 41e containing an A-carboxyalky I -group demonstrate sufficient enhancement (up to 16 times) in the presence of avidin. Nevertheless, the presence of hydrolases like lysozyme or trypsin has only minor effects on the fluorescence intensity of squaraine dyes. 

The tissue surrogates described here clearly represent a simplification of real FFPE tissues. However, they represent a useful and efficient construct for the evaluation and optimization of tissue extraction conditions for proteomic studies. More informative studies will likely be realized by using more complex tissue surrogates, which can be created by incorporating additional proteins into lysozyme solutions. Tissue surrogates comprised of up to five proteins have been successfully analyzed by MS (Fowler, unpublished data). Additionally, RNA, DNA, lipids, or carbohydrates can be added at nanomolar to millimolar concentrations to increase the complexity of the model system to better mimic whole tissue. The use of these more complex tissue surrogates should facilitate the development of protein recovery protocols optimal for proteomic investigation. 

Internal water is an integral part of a protein structure. Even globular proteins of small size are observed to contain buried water molecules. Examples are pancreatic trypsin inhibitor, with 58 amino acid residues and 4 interior water molecules, lysozyme with 129 residues and 4 waters, and larger proteins like ac-tinidin with 218 residues which may contain 10 to 20 molecules of internal water (Fig. 19.13). These water molecules can be buried deep inside the globular proteins or located in cavities near the surface. In some cases, therefore, the distinction in-ternal/external water can be ambiguous. 

Primary saliva is modified in the intercalated, striated, and excretory (collecting) ducts that lead from the acini to the mouth. Water and electrolyte transport into the saliva is beUeved to occur in the intercalated ducts. Striated ducts are responsible for electrolyte transport such as secretion of potassium and reabsorption of sodium ions. A transport of proteins Like IgA, lysozyme, and kallikrein [and may be Hsp70 (2)] probably exists in the striated duct as well. An electrolyte transport in the excretory (collecting) ducts is also suspected (1). 

Proteins like insulin, myoglobin and lysozyme were also loaded onto the non-coated CE capillary and collected for nES/MS analysis and Edman sequencing. Because the peak width of proteins is larger than that of the peptides on the non-coated column, the window is relatively wide (about 10 minutes) under 7.5 kV for fraction collection. Figure 8a is the nES/MS spectrum of... 

As later chapters will demonstrate, the chemical reactions carried out by proteins like hemoglobin and lysozyme depend on the precise orientation of atoms involved in binding and acting on substrates. The fact that catalysis can occur in enzyme crystals argues that these same orientations are preserved and that the structure of the enzyme must be the same as that found in solution. 

There are some informations about monotonous decrease of the equilibrium surface tension, dilatational elasticity, and adsorption of lysozyme for non-ionic surfactant decyl dimethyl phosphine oxide (Cj DMPO) as the concentration of surfactant increases in the mixture. However, in the case of mixtures of non-ionic surfactants with more flexible proteins like P-casein, the elasticity of the interfacial layer decreases before passing through a maximum as the concentration of surfactant increases [7], Possibly, the weaker interfacial network formed by P-casein as compared to globular proteins determines the dilatational response of the mixtures. The same picture was shown for the system P-casein mixed with dodecyl dimethyl phosphine oxide (C,2DMPO). For all studied frequencies (0.005-0.1 Hz) the elasticities for adsorption layers have a maximum about 4x10" mol/1 Cj2DMPO concentration. It was shown the obtained values are very close to those measured for the surfactant alone. Thus, in this concentration region the surfactant dominates the surface layer. In our case we have... 

Norde and Anusiem [15] examined adsorption, desorption, and readsorption of bovine serum albumin (BSA), a-lactalbumin, and lysozyme on silica and hematite surfaces. They found that soft proteins like BSA and a-lactalbumin might adsorb even under the seemingly unfavorable conditions of a hydrophihc, electrostatically repelling surface. Moreover, they found that preadsorbed BSA and a-lactalbxunin, compared with native BSA and a-lactalbumin, resulted in a higher affinity for the adsorbent. On the other hand, lysozyme, which is considered a hard protein, did not show any difference in adsorptive behavior with the repetition of the adsorption step. 

The particle has a head, within which the viral DNA is folded, and a long, fairly complex tail, at the end of which is a series of tail fibers. During the attachment process, the vims particles first attach to the cells by means of the tail fibers. These tail fibers then contract, and the core of the tail makes contact with the cell envelope of the bacterium. The action of a lysozyme-like enzyme results in the formation of a small hole. The tail sheath contracts and the DNA of the vims passes into the cell through a hole in the tip of the tail, the majority of the coat protein remaining outside. The DNA of T4 has a total length of about 50 /xm, whereas the dimensions of the head of the T4 particle are 0.095 Am by 0.065 fim. This means that the DNA must be highly folded and packed very tightly within the head. 

---