Proteins ultraviolet

In view of these results, two observations may be made (a) as a corollary to studies of protein ultraviolet spectra in any particular nonaqueous solvent, the spectral properties of relevant simple compounds in that solvent must be investigated and (5) any changes in protein spectra produced as a result of modification of the native protein conformation in a particular nonaqueous solvent must be superimposed on changes resulting simply from the replacement of the aqueous environment by the nonaqueous one of generally different polarizability and refractive index. In the extreme case, for example, it may make little or no difference spectrally whether the aromatic chromophores remain internally bound within the protein molecule, or whether they become exposed to the solvent, and hence no useful information about protein conformations can be expected. More studies have to be made to clarify to what extent spectral changes can be useful in the investigation of proteins in nonaqueous solvents. 

Serum proteins ultraviolet determination of tyrosine and tryptophan composition of protein fractions separated from blood serum by electrophoresis... 

If unidentified peaks are detected the stability of the protein under the chromatographic conditions should be checked. In all analytical investigations of proteins on SEC columns it is desirable to be able to monitor the eluted peaks at a very high sensitivity of the ultraviolet detector. Therefore, very pure (analytical grade) salts and buffers should be used. 

From Wetlaufer, D.B., 1962. Ultraviolet spectra of proteins and amino acids. Advances in ProLeia ChemisLry 17 303-390.)... 

Essential for induction ofthe/Z-5 gene in inflammatory reactions is the binding site for nuclear factor kappa B (NF-kB). NF-kB responds to cytokines, stress, free radicals, ultraviolet irradiation, and bacterial, viral, or even parasitic antigens [2]. NF-kB stands for a family of subunits, which form homo-, and heterodimers. All NF-kB proteins share a highly conserved DNA-binding/dimerization domain called the Rel homology domain (RHD) consisting of two (3-strand core domains... 

Most frequently, SEC with dextran-, pullulan-, or polystyrene calibration standards has been used to characterize the molecular properties of xylans. However, as for viscometric studies [108], a sufficient solvent ionic strength is a prerequisite for useful SEC measurements of charged polysaccharides, including glucuronoxylans [111-113]. An advantage of the SEC technique is that the presence of protein and phenolic components or oxidative changes can be detected by simultaneous ultraviolet (UV) detection. 

Luminescence measurements on proteins occupy a large part of the biochemical literature. In what surely was one of the earliest scientific reports of protein photoluminescence uncomplicated by concurrent insect or microorganism luminescence, Beccari (64), in 1746, detected a visible blue phosphorescence from chilled hands when they were brought into a dark room after exposure to sunlight. Stokes (10) remarked that the dark (ultraviolet) portion of the solar spectrum was most efficient in generating fluorescent emission and identified fluorescence from animal matter in 1852. In general, intrinsic protein fluorescence predominantly occurs between 300 nm and 400 nm and is very difficult to detect visually. The first... 

My interest at that time revolved around evaluating optical rotary dispersion data [12]. The paired values of optical rotation vs. wavelength were used to fit a function called the Drude equation (later modified to the Moffitt equation for William Moffitt [Harvard University] who developed the theory) [13]. The coefficients of the evaluated equation were shown to be related to a significant ultraviolet absorption band of a protein and to the amount of alpha-helix conformation existing in the solution of it. 

Amino acids do not absorb visible hght and thus are colorless. However, tyrosine, phenylalanine, and especially tryptophan absorb high-wavelength (250—290 nm) ultraviolet light. Tryptophan therefore makes the major contribution to the abihty of most proteins to absorb hght in the region of 280 nm. 

When the chip is rinsed, fluorescent DNA remains bound to all those areas of the chip that have complementaiy sequences. Areas of the chip whose sequences are not complementary do not bind to the DNA. When the chip is rinsed and subsequently exposed to ultraviolet light, the areas with bound DNA fluoresce, generating light from each area to which the DNA has bound, hi contrast, areas of the chip that contain noncomplementary sequences remain dark. The fluorescence pattern reveals which protein synthesis processes have been modified in the cancerous cell, and this in turn helps physicians determine what treatment is most likely to be effective against the cancer. 

SASPs comprise about 10-20% of the protein in the dormant spore, exist in two forms alfi and y) d are degraded during germination. They are essential for expression of spore resistance to ultraviolet radiation and also appear to be involved in resistance to some biocides, e.g. hydrogen peroxide. Spores (a /3 ) deficient in a//3-type SASPs are much more peroxide-sensitive than are wild-type (normal) spores. It has been proposed that in wild-type spores DNA is saturated with a/j3-type SASPs and is thus protected from free radical damage. 

Purines absorb only ultraviolet light and they contribute to structural colors (white and silver) in animals. Pterines are generally yellow, orange, or red pigments. Because they are amphoteric molecules, the absorption spectra depend on the pH and present three or two absorption maxima, usually one in the visible region. Sepiapterin has an absorption maximum at 340 nm in O.IM NaOH and at 410 nm in O.IM HCl." Leucopterin has three maxima 240, 285, and 340 nm. Xanthopterin has two 255 and 391 nm. Because they are conjugated with proteins, pterins show bathochromic shifts in vivo. They also present fluorescence when excited with UV light. 

Different types of gel materials, such as polysaccharides, proteins and synthetic polymers, are now used to entrap biocatalysts. Among them, photo-crosslinkable resin prepolymer ENTP-4000 as shown in Eig. 7 is more useful compared to others. Entrapment of biocatalysts should be carried out under the illumination of near ultraviolet hght within 3-5 min, by which high temperatures, shifts of pH to extremely alkahne or acidic sides are avoided. ENTP-4000, hydrophobic photo-crosslinkable resin prepolymer, is one of the most suitable prepolymers for entrapment of p-glucosidase. Molecular weight of its main chain is about 4000. 

Although cytochalasin B normally functions as a reversible inhibitor of glucose transport, upon exposure to ultraviolet light a small proportion of the bound cytochalasin B molecules become covalently linked to the transporter protein [128-130]. Photolabelling is inhibitable by D-glucose and other transported sugars but not by... 

Hapten density is important for both immunization and assay performance, and hence the extent of conjugation or hapten density should be confirmed by established methods. A characteristic ultraviolet (UV) or visible absorbance spectrum that distinguishes the hapten from the carrier protein or use of a radiolabeled hapten can be used to determine the degree of conjugation. If the hapten has a similar A. iax to the protein, the extent of incorporation can still be estimated when the concentration of the protein and the spectral characteristics of the hapten and protein are known. The difference in absorbance between the conjugate and the starting protein is proportional to... 

Nonpharmacologic Therapy Pruritus associated with CKD is difficult to alleviate. It is important to evaluate other potential dermatologic causes of pruritus to maximize the potential for relief. Adequate dialysis is generally the first line of treatment in patients with pruritus. However, this has not been shown to decrease the incidence of pruritus significantly. Maintaining proper nutritional intake, especially with regard to dietary phosphorus and protein intake, may lessen the degree or occurrence of pruritus. Patients who do not attain relief from other measures may benefit from ultraviolet B phototherapy. 

Hillenkamp, F. Karas, M. Mass spectrometry of peptides and proteins by matrix-assisted ultraviolet laser desorption/ionization. Meth. Enzymol. 1990,193 (Mass Spectrom.), 280-295. 

Chan, T.-W. D. Thomas, I. Colburn, A. W. Derrick, P. J. Initial velocities of positive and negative protein molecule-ions produced in matrix-assisted ultraviolet laser desorption using a liquid matrix. Chem. Phys. Lett. 1994,222,579-585. 

It has been demonstrated in other cell types that lutein can inhibit expression of MMPs and/ or activity (Philips et al., 2007). For example, in dermal fibroblasts lutein inhibits expression of MMP-1 and decreases levels of MMP-2 protein (Philips et al., 2007). In melanoma cells, lutein inhibits MMP-1 expression while stimulating TIMP-2 (Philips et al., 2007). Moreover it has been shown that lutein inhibits elastin expression in fibroblasts subjected to oxidative stress by exposure to ultraviolet light (Philips et al., 2007). These results clearly indicate that lutein can play an important role in remodeling of the extracellular matrix. 

Detection in 2DLC is the same as encountered in one-dimensional HPLC. A variety of detectors are presented in Table 5.2. The choice of detector is dependent on the molecule being detected, the problem being solved, and the separation mode used for the second dimension. If MS detection is utilized, then volatile buffers are typically used in the second-dimension separation. Ultraviolet detection is used for peptides, proteins, and any molecules that contain an appropriate chromophore. Evaporative light scattering detection has become popular for the analysis of polymers and surfactants that do not contain UV chromophores. Refractive index (RI) detection is generally used with size exclusion chromatography for the analysis of polymers. 

Demchenko AP (1986) Ultraviolet spectroscope of proteins. Springer-Verlag, Heidelberg, New York... 

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