Protein A, properties

John.son, L. N., and Barford, D., 1994. Electro.static effects in die control of glycogen pho.sphoryla.se by pho.sphorylation. Protein Science 3 1726-1730. Di.scn.s.sion of die pho.sphate group s ability to deliver two negative charges to a protein, a property that no amino acid side chain can provide. 

The glutathione transferase (GST) comprises multifunctional proteins coded by a multigene family. These enzymes are both cytosolic and microsomal and function as homodimers and heterodimers. They exist as four classes in mammals. The human enzymes comprise the following dimers Al-1, Al-2, A2-2, A3-3 (alpha class), Mla-la, Mla-lb, Mlb-lb, Mla-2, M2-2, M3-3 (mu class), Pl-1 (pi class), Tl-1 (theta class), and three microsomal enzymes (MIC). The GST Al-1 and Al-2 are also known as ligandin when they act as binding or carrier proteins, a property also displayed by Mla-la, Mlb-lb and also by GSH (pi class). 

The protein sequence database is also a text-numeric database with bibliographic links. It is the largest public domain protein sequence database. The current PIR-PSD release 75.04 (March, 2003) contains more than 280 000 entries of partial or complete protein sequences with information on functionalities of the protein, taxonomy (description of the biological source of the protein), sequence properties, experimental analyses, and bibliographic references. Queries can be started as a text-based search or a sequence similarity search. PIR-PSD contains annotated protein sequences with a superfamily/family classification. 

Soybean Protein Isolates. Soybean protein isolates, having a protein content of >90 wt%, are the only vegetable proteins that are widely used in imitation dairy products (1). Most isolates are derived from isoelectric precipitation, so that the soybean protein isolates have properties that are similar to those of casein. They are insoluble at thek isoelectric point, have a relatively high proportion of hydrophobic amino acid residues, and are calcium-sensitive. They differ from casein in that they are heat-denaturable and thus heat-labile. The proteins have relatively good nutritional properties and have been increasingly used as a principal source of protein. A main deterrent to use has been the beany flavor associated with the product. Use is expected to increase in part because of lower cost as compared to caseinates. There has been much research to develop improved soybean protein isolates. 

Cells contain thousands of different proteins. A major problem for protein chemists is to purify a chosen protein so that they can study its specific properties in the absence of other proteins. Proteins have been separated and purified on the basis of their two prominent physical properties size and electrical charge. A more direct approach is to employ affinity purification strategies that take advantage of the biological function or similar specific recognition properties of a protein (see Table 5.5 and Chapter Appendix). 

S-acylated proteins include many GTP-binding regulatory proteins (G proteins), including most a subunits of heterotrimeric G-proteins and also many members of the Ras superfamily of monomeric G proteins, a number of G protein-coupled receptors, several nonreceptor tyrosine kinases, and a number of other signaling molecules, -acylation is posttranslational and reversible, a property that allows the cell to control... 

Yu, M., Goldberg, S., Goldberg, A.L. (1W2). Heat shock in Escherichia coli alters the protein-binding properties of the chaperonin groEL by inducing its phosphorylation. Nature 357, 167-169. 

In reconstitution experiments, the self-assembly of the pore-forming protein a-hemolysin of Staphylococcus aureus (aHL) [181-183] was examined in plain and S-layer-supported lipid bilayers. Staphylococcal aHL formed lytic pores when added to the lipid-exposed side of the DPhPC bilayer with or without an attached S-layer from B coagulans E38/vl. The assembly of aHL pores was slower at S-layer-supported compared to unsupported folded membranes. No assembly could be detected upon adding aHL monomers to the S-layer face of the composite membrane. Therefore, the intrinsic molecular sieving properties of the S-layer lattice did not allow passage of aHL monomers through the S-layer pores to the lipid bilayer [142]. 

When they are protonated, amines are compatible with water, a property critical in biochemical processes because it helps biological macromolecules dissolve in water. The N—H bond in an amine is fairly easy to break, so amines participate in the formation of several important classes of polymers, including nylon and proteins. 

C20-0107. One of the most common approaches to the investigation of metaiioproteins is to repiace the naturaiiy occurring metai ion with a different one that has a property advantageous for chemicai studies. For exampie, zinc proteins are often studied by visibie spectroscopy after Co has been substituted for Zn . Expiain, using crystai fieid energy diagrams, why Co is a better metai than Zn for visibie spectroscopy. 

Casini, A., Cinellu, M.A., Minghetti, G., Gabbiani, C., Coronnello, M., Mini, E. and Messori, L. (2006) Structural and solution chemistry, antiproliferative effects, and DNA and protein binding properties of a series of dinudear gold(l II) compounds with bipyridyl ligands. Journal of Medicinal Chemistry, 49, 5524. 

WPI, whey protein isolates. Properties of nonextmded WPI pH 6.8, protein 88.9%, insoluble (denatured) 28.0%, and digestibility 87.7%. Means with different letters within a column are significantly (p < 0.05) different. 

Patel S, Mackerell AD, Brooks CL (2004) CHARMM fluctuating charge force field for proteins II -Protein/solvent properties from molecular dynamics simulations using a nonadditive electrostatic model. J Comput Chem 25(12) 1504-1514... 

Finally, animal, plant and microbial tissues have been shown to contain the iron storage protein ferritin. The animal protein has been extensively studied, but the mechanism of iron binding has not been completely resolved (29). Animal tissues contain, in addition, a type of granule comprised of iron hydroxide, polysaccharide and protein. The latter, called hemosiderin, may represent a depository of excess iron (30). Interestingly, a protein with properties parallel to those of ferritin has been found in a mold. Here the function of the molecule can be examined with the powerful tools of biochemical genetics (31). 

A. Properties of the Intestinal Fatty Acid Binding Protein. 103... 

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