Conjugates protein

Lysine residues are commonly present on the surface of the majority of proteins and, therefore, are an easy target for conjugations. There are several 

FIGURE 3.36 Bioconjugation strategies for cysteine (left) and lysine (right) residues. 

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FIGURE 4.49 Isolation of a complex protein conjugate on Toyopearl HW-50S. Column 22 mm X 83 cm. Sample Fraction from crude Tetrahymena H2A containing the ubiquitin-histone conjugate uH2A. Elution 10 nM HCI. Flow rate 0.1 ml/min. Detection UV at 230 nm. 

LIPOPROTEINS. Blood plasma lipoproteins are prominent examples of the class of proteins conjugated with lipid. The plasma lipoproteins function primarily in the transport of lipids to sites of active membrane synthesis. Serum levels of low density lipoproteins (LDLs) are often used as a clinical index of susceptibility to vascular disease. 

FIGURE 25.7 The pathway of palmhate synthesis from acetyl-CoA and malonyl-CoA. Acetyl and malonyl building blocks are introduced as acyl carrier protein conjugates. Decarboxylation drives the /3-ketoacyl-ACP synthase and results in the addition of two-carbon units to the growing chain. Concentrations of free fatty acids are extremely low in most cells, and newly synthesized fatty acids exist primarily as acyl-CoA esters. 

Synthetically produced or modified carbohydrate-protein conjugates are sometimes referred to as neoglycoproteins. The nomenclature for the carbohydrate-containing substituents in such structures is analogous to sequential oligosaccharide nomenclature (2-Carb-37.2)... 

Maggs, J.L., Grabowski, P.S., and Park, B.K. (1983). Drug protein conjugates. 2. An investigation of the irreversible binding and metabolism of 17-alpha-ethinyl estradiol in vivo. Biochemical Pharmacology 32, 301-308. 

The nanostructured molecular arrangements from DNA developed by Seeman may find applications as biological encapsulation and drug-delivery systems, as artificial multienzymes, or as scaffolds for the self-assembling nanoscale fabrication of technical elements. Moreover, DNA-protein conjugates may be anticipated as versatile building blocks in the fabrication of multifunctional supramolecular devices and also as highly functional-... 

Figure 1 Schematic of the quasi-equihbria using heterologous haptens in coating antigen immunoassay formats. Ka represents the equilibrium constant for binding of antibody (Y) to target analyte (A). Kh is the equilibrium constant for the binding of antibody to hapten-protein conjugate (H-) immobihzed on a solid phase...

Alternatively, competitive ELISA can be used to estimate the hapten density if an antibody that specitically recognizes the hapten is available. At first observation this approach seems circular because the immunoassay developed is used to determine hapten density on proteins used for immunization. However, if a small molecule mimic of the protein conjugate is used as a standard, the method can be accurate. For example, a hapten containing a carboxylic acid can be coupled to phenethylamine or tyramine, its structure confirmed and the material used to generate a calibratron curve to estimate hapten density. 

A monoclonal antibody-based ELISA has been utilized to determine ceftiofur levels in milk. The authors noted that matrix interference occurred, but a 1 100 dilution lowered the interference, and a 1 1000 dilution eliminated the matrix interference. Because of the high dilution, samples could not be measured below l.Opgkg The assay measured ceftiofur, its major metabolite desfuroylceftiofur, and ceftiofur protein conjugates and has been utilized to measure residues in milk from cows treated with therapeutic doses of the drug. The results from the incurred residue correlated well with a previous study using radiolabeled ceftiofur, confirming the detection of a metabolite that was not detected by HPLC. 

SS Wong. Chemistry of Protein Conjugation and Crosslinking. Boca Raton, FL CRC Press, 1993. 

Schneerson R, Kubler-Kielb J, Liu TY et al (2003) Poly(y-D-glutamic acid) protein conjugates induce IgG antibodies in mice to the capsule of Bacillus anthracis a potential addition to the anthrax vaccine. Proc Natl Acad Sci USA 100 8945-8950... 

Wang TT, Fellows PF, Leighton TJ et al (2004) Induction of opsonic antibodies to the gamma-D-glutamic acid capsule of Bacillus anthracis by immunization with a synthetic peptide-carrier protein conjugate. FEMS Immunol Med Microbiol 40 231-237... 

Kubler-Kielb J, Liu TY, Mocca C et al (2006) Additional conjugation methods and immunogenicity of Bacillus anthracis poly-y-D-glutamic acid-protein conjugates. Infect Immun 74 4744 1749... 

Wong SS (1991) Chemistry of Protein Conjugation and Cross- linking. CRC Press, Boston... 

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