Modified protein

Chromatographic evidence supporting the similarity of the yellow chromophores isolated from aged human brunescent cataract lenses and calf lens proteins modified... 

Radoff, S., Vlassara, H. and Cerami, A. (1988). Characterisation of a solubilised cell surface binding protein on macrophages specific for proteins modified non-enzymatically by advanced... 

CrylAc protein Modified EPSPS Acetolactate synthase (csr-1) CrylllA, PVY coat protein CrylllA, PLRV repUcase Nitrilase, CrylAc protein... 

The present report describes preparation and use of new protein modifying reagents, namely methoxypoly(ethylene glycol)-N-succinimidyl carbonate (SC-PEG) and its bifunctional analog, polyethylene glycol)-bis-N-succinimidyl carbonate (BSC-PEG). 

Several markers of oxidative stress have been identified in AMD retinas, including proteins modified by products of lipid peroxidation (Crabb et al., 2002 Gu et al., 2003 Hollyfield et al., 2003). Overall, there is growing body of evidence implicating oxidative stress in the development and progression of AMD (Anderson et al., 2002 Beatty et al., 2000 Seddon et al., 2004). 

Proteins modified with 2-iminothiolane are subject to disulfide formation upon sulfhydryl oxidation. This can cause unwanted conjugation, potentially precipitating the protein. The addition of a metal-chelating agent such as EDTA (0.01-0.1M) will prevent metal-catalyzed oxidation and maintain sulfhydryl stability. In the presence of some serum proteins (i.e., BSA) a 0.1M concentration of EDTA may be necessary to prevent metal-catalyzed oxidation, presumably due to the high contamination of iron from hemolyzed blood. 

Occasionally, a protein modified in this manner will begin to precipitate as the reaction proceeds. Stopping the reaction earlier or adding a smaller quantity of modifying reagents may limit this effect. 

Hemmila, 1988) (see Chapter 9, Section 9). The most commonly used lanthanides for this purpose are europium (Eu3+), terbium (Tb3+), and samarium (Sm3+). Proteins modified with DTTA and complexed with lanthanide metal ions form the basis for unique fluorescent probes possessing long lived signals upon excitation. 

Protein modified via amide bond and having terminal maleimide available for coupling with second protein... 

The use of discrete PEG spacers in the construction of biotinylation compounds not only increases the water solubility of the modification reagent itself, but significantly increases the hydrophilicity and stability of proteins modified with them. Even when high modification levels... 

Bait proteins modified with Sulfo-SBED may precipitate if the level of modification is too high, primarily due to the hydrophobic nature of the crosslinker and the biotin handle. To prevent precipitation or at least minimize it, adjust the molar excess of Sulfo-SBED over the bait protein to a level where the protein remains in solution. Some precipitation may be removed by centrifugation or filtration prior to use. 

Surfactant has a similar amphoteric structure as lipid, which makes it possible to form a stable membrane the same as a lipid membrane and can be used to embed proteins. A surfactant membrane has many characteristics similar to those of a biomembrane, so that it can retain the bioactivities of proteins well. The process of preparing a sur-factant/protein-modified electrode is simple and viable. There are usually two methods... 

CNTs can be functionalized with protein via non-covalent bond (Li et al., 2005 Kim et al., 2003 Mitchell et al., 2002). For example, (beta-lactamase I, that can be immobilized inside or outside CNTs, doesn t change enzyme s activity (Vinuesa and Goodnow, 2002). Taq enzyme can attach to the outside of CNT, and doesn t change its activity (Cui et al., 2004). Peptide with Histidine and Tryptophan can have selective affinity for CNT(Guo et al., 1998). Monoclonal antibody can attach to SWNTs. Protein-modified CNTs can be used to improve its biocompatibility and biomolecular recognition capabilities (Um et al., 2006). For example, CNTs functionalized with PEG and Triton X-100 can prevent nonspecific binding of protein and CNTs. Biotin moiety is attached to the PEG chains Streptavidin can bind specifically with biotin-CNT (Shim et al., 2002). 

Fig. 17. Bioelectric catalysis on a designed heme protein modified Au electrode. Schematic electron transfer. Reprinted with permission from Ref. (7S7) copyright 1999 American Chemical Society.

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