Minor proteins

Arachin, the counterpart of glycinin in peanuts, consists of subunits of 60,000—70,000 mol wt which on reduction with 2-mercaptoethanol yield polypeptides of 41,000—48,000 and 21,000 mol wt (17) analogous to the behavior of glycinin. In addition to the storage proteins, oilseeds contain a variety of minor proteins, including trypsin inhibitors, hemagglutinins, and enzymes. Examples of the last are urease and Hpoxygenase in soybeans. 

Organization into macromolecular structures. There are no apparent templates necessary for the assembly of muscle filaments. The association of the component proteins in vitro is spontaneous, stable, and relatively quick. Filaments will form in vitro from the myosins or actins from all three kinds of muscle. Yet in vitro smooth muscle myosin filaments are found to be stable only in solutions somewhat different from in vivo conditions. The organizing principles which govern the assembly of myosin filaments in smooth muscle are not well understood. It is clear, however, a filament is a sturdy structure and that individual myosin molecules go in and out of filaments whose structure remains in a functional steady-state. As described above, the crossbridges sticking out of one side of a smooth muscle myosin filament are all oriented and presumably all pull on the actin filament in one direction along the filament axis, while on the other side the crossbridges all point and pull in the opposite direction. The complement of minor proteins involved in the structure of the smooth muscle myosin filament is unknown, albeit not the same as that of skeletal muscle since C-protein and M-protein are absent. 

Taylor RS et al. Proteomics of rat liver Golgi complex minor proteins are identified through sequential fractionation. Electrophoresis 2000 21 3441-3459. 

According to the predominant component, the binders are usually divided into protein, oil, polysaccharide, and resin binders. In this section we shall focus on protein binders but it is worth mentioning that in the majority of natural non-protein binders a minority protein component is usually present as well. Thus many of the analytical techniques described here can be (with certain limitations) applied to them as well. Although in colour layers of artworks and particularly in paintings protein binders are relatively abundant (up to 10%), their identification is often limited by a small amount of sample that is usually available for analysis (tens or hundreds of micrograms at most [6]). 

Liver Minor protein stores helps muscle metabolize protein Muscle Major site of protein stores for metabolic needs Adipose No significant protein stores Red blood cells No significant protein stores Brain No significant protein stores... 

Several of the minor proteins of the MFGM have been isolated and partially characterized (Keenan and Dylewski, 1995). A systematic nomenclature has not been developed for the MFGM proteins and most are referred to by their relative electrophoretic mobility on SDS-PAGE and whether or not they are glycoproteins. The proteins of the MFGM represent approximately 1 % of the total proteins in milk. 

During the nineteenth and early twentieth centuries, separation of the proteins was limited to casein and the classical lactalbumin and lacto-globulin fractions of the whey proteins. Subsequent work has resulted in the identification and characterization of numerous proteins from each of these fractions. A classification system of the known proteins in milk developed by the American Dairy Science Association s (ADSA) Committee on Milk Protein Nomenclature, Classification, and Methodology (Eigel et al 1984) is summarized and enlarged to include the minor proteins and enzymes in Table 3.1. 

In addition to the major protein fractions indicated above, some minor proteins have been isolated or identified in milk. 

McKenzie, H. A. 1971. Whey proteins and minor proteins (3-Lactoglobulins. In Milk Proteins Chemistry and Molecular Biology, Vol. 2. H.A. McKenzie (Editor). Academic Press, New York, pp. 257-330. 

Highly specific antibodies directed against minor proteins, present in small amounts in biological fluids, or against nonsoluble cytoplasmic or membranous proteins, are often difficult to obtain. The main reasons for this are the small amounts of protein available after the various classical purification processes and the low purity of the proteins. 

Both major and minor protein components separated in this way were Ci types. This was established when it was found that either acted in synergism with a mixture of the Cx and / -glucosidase activities to the same extent in solubilizing cotton cellulose (Table II). Furthermore, both components were cellobiohydrolases in that they could degrade H3PO4 cellulose to cellobiose. 

More recently it has become clear that NAP-taurine passes through other membranes more readily than those of erythrocytes. It has proved difficult, for instance, to prevent its penetration into other types of mammalian cells. This limits its use for labeling membranes from the external medium. An even more important problem is that the molecule appears to bind to cell membranes like a detergent (Dockter, 1979 Richards and Brunner, 1980) and it seems that a number of the minor proteins labeled in intact erythrocytes penetrate the membrane deeply from the cytoplasmic side but do not span it. These proteins are accessible to NAP-taurine molecules that reach down into the hydrocarbon region of the bilayer. 

Screening for potential bioactivity among minor proteins of milk, egg, vegetables, cereals, and fruits. 

Gliadins are prolamins, a group of plant storage proteins with a high proline content, found in the seeds of cereal grains wheat (gliadin), barley (hordein), rye (secalin), corn (zein) and, as a minor protein, avenin in oats. 

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