Surface production proteins

The mechanism of antiperspinant action has not been fully estabHshed but probably is associated with blockage of ducts leading to the surface by protein denaturation by aluminum salts. The FDA has mandated that an antiperspinant product must reduce perspiration by at least 20% and has provided some guidelines for testing finished products. Some antiperspinant chemicals are Hsted in Table 14 (63). 

In vitro, chlorhexidine can adversely affect gingival fibroblast attachment to root surfaces. Furthermore, protein production in human gingival fibroblasts is reduced at chlorhexidine concentrations that would not affect cell proliferation. Such findings corroborate earlier studies showing delayed wound healing in standardized mucosal wounds after rinsing with 0.5% chlorhexidine solution. 

Figure 3.4 Optimization of conditions for crystallization of tryptophanyl-tRNA synthetase. Photo insets show crystals obtained from various conditions represented by points on the surface. Coordinates of the surface are protein concentration (PROTEIN), product of protein concentration and precipitant concentration (PRO-PPNT), and the shape of the crystal as reflected by the ratio of its two smallest dimensions, width and length (WL RATIO). From C. W. Carter, in Methods in Enzymology 276, C. W. Carter and R. M. Sweet, eds., Academic Press, New York, 1997, p. 75. Reprinted with permission.

While lipoproteins are the products of many different genes, the major apolipoproteins share properties distinguishing them from most lipid-free and membrane-associated proteins. For example, apolipoproteins consist of a single polypeptide chain that has relatively little tertiary structure. Most apolipoproteins contain stretches of amphipathic alpha-helix, whose hydrophobic face can be turned to the lipid surface of the particle. The apolipoproteins are flexible, as is reflected in their unusually small free energy of unfolding. As these apolipoproteins expand and contract at the cell surface, different protein domains are exposed that are detectable with monoclonal antibodies. These properties reflect the role of apolipoproteins at the surface of lipoprotein particles whose size changes as they circulate. 

Figures 12a-d present the surface appearances of copper-2% zinc alloy exposed to the phosphated-saline albumin-globulin-fibrinogen solution. The as-immersed surface (Figures 12a-b) exhibited a protein layer, protein accumulation, and copper chloride phosphates as corrosion products. Polarization at —0.3 V eliminated the outer surfaces of protein accumulation and of corrosion products. Only the underlying protein layer was observed (Figure 11c). Polarization at -0.5 V desorbed most of the protein (Figure lid).

Schmidt AM, Yan SD, Brett J, Mora R, Nowygrod R, Stem D. Regulation of human mononuclear phagocyte migration by cell surface-binding proteins for advanced glycation end products. J Clin Invest 1993 91 2155-2168. 

They employed open-column HIC to determine the relative surface hydro-phobicity of various strains of Staphylococcus aureus. They found a good correlation between the adsoption of the various strains to octyl Sepharose and the production of the surface antigen protein A. This protein is known to have exposed hydrophobic areas as bound to the cell surface (Sjodahl, 1977). 

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