Proteins in disease

Isobaric labels thus permit quantitative information regarding protein expression levels in multiple samples analyzed simultaneously by MS. The multiplexed capability of these reagents allows the measurement of peptides and proteins in diseased samples, treated samples, and normal samples all in the same experiment. In addition, since all peptides from a given protein get labeled at their N-termini, the MS analysis generates more than one peptide signal, which can be used to confirm protein identity with greater confidence than using a cysteine label, like ICAT. 

As previously mentioned, flaxseed is a rich source of dietary fiber (28%). Dietary fiber has been widely viewed as a component essential to lowering the risk of colon cancer. The flaxseed protein is similar to soy thus may be beneficial to health. Bhathena et al. (2002) first reported that flaxseed protein was effective in lowering plasma cholesterol and triacylglycerides (TAG) compared to soy and casein protein in male F344 and obese SHR/N-cp rats. The role of protein in disease prevention warrants further investigation. Components, such as PAs and flavonoids, may also contribute to the health benefits of flaxseed. 

Cell-Specific Targeting. Peptides that can home in on specific cell types have enormous potential both in basic research and therapeutic applications (121). Therapeutic applications include identification of specific cell surface proteins in diseased cells as diagnostic agents and gene delivery agents. 

DDAH itself may also have potential as a therapeutic protein in disease states marked by excess N dimethyl-L-arginine. For example, overexpression of DDAH has beneficial effects in transgenic mouse models of graft coronary artery disease and can enhance sensitivity to insulin. DDAH may also have beneficial effects in treating chronic kidney disease, as overexpressed DDAH appears to slow progression of renal dysfunction in rat models. " Elevated asymmetric dimethylarginine (ADMA) levels have also been identified in the development of chronic lung diseases, specifically pulmonary fibrosis. However, the causal relationship between ADMA and these conditions has yet to be explored in detail. ... 

The main approach of proteomic analysis of brain pathology is to use comparative 2D-page separation of constituent proteins in diseased versus normal samples. This is usually followed by gel image analysis to identify alterations in the intensify of specific spots compared to the normal state and subsequent excision of the abnormal spots and identification by mass spectrometiy or peptide sequencing. The main types of samples, which have been analysed by these means, are human biopsies or postmortem samples and mouse models of human disease. 

CAT s antibodies can be used directly to analyze the presence or absence of a protein in diseased and normal tissue to give evidence of guilt by association. CAT can test whether proteins implicated by an association with disease have a direct role in causing that disease by using antibodies to directly neutralize or possibly mimic the effects of the protein in both in vitro and in vivo models of the disease. This gives data about the involvement of the protein as a causative agent in the disease. 

If the concentrations of proteins in the cerebrospinal fluid are abnormally high, above 200 mg/100 ml, the resulting curves may be deformed to a drawn-out, inclined double hump. Such a finding indicates a massive penetration of serum proteins into the cerebrospinal fluid since serum proteins in disease exhibit low absolute and relative denaturation capa-bihties, such curves are lower, and the calculation produces unpropor-tionally low values. Such a curve is termed the serum tsrpe curve, and no calculation is done at all. 

The term proteome refers to the total protein complement encoded within, and expressed from, a genome. Proteomics is the systematic study of those proteins, be they derived from the entire genome, from particular tissues or cells, or originating from healthy as well as diseased states. Proteomics has several, widely differing aims, including (1) identification of proteins on a large scale, (2) identification of post-translational modifications (PTMs) (Section 3.5.1.5), (3) studies of protein-protein interactions, (4) comparison of the differential expression of specific proteins in healthy and diseased states, (5) exploration of the role(s) of specific proteins in metabolic pathways, and (6) development of drugs based on the presence/absence of specific proteins in diseases. 

The studies on plasma proteins in disease have been carried out very largely by neutral-salt precipitation and by electrophoretic analysis, to some extent also by immunochemical techniques, ultracentrifugation, and other methods. It is important to appreciate that such procedures yield only crude fractional separations, which are reproducible when applied by standardized technique and often helpful as first approximations, but do not satisfactorily resolve the plasma proteins into anything... 

The term euglobulin" as employed in connection with the plasma proteins in disease ordinarily refers to the Howe euglobulin fraction. The same term may be used, however, to indicate proteins precipitated by 0.33-cnturated ammonium sulfate solution, proteins precipitated out of serum by addition of distilled water or by dialysis (proteins insoluble in distilled water near their isoelectric points but soluble in dilute sidt solutions), or proteins precipitated out of serum by lowering the pH, usually by introducing carbon dioxide. Needless to say, much confusion has resulted from these different usages. 

This system has been applied only sporadically to study the blood proteins in disease, notably by Rapoport, Rubin, and Chaffee (296) and by Wuhrmann and Wunderly (383). Rapoport et al. fractionally precipitated the sera of normal infants, children, and adults with concentrations... 

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