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Nhs Activation Of Sepharose 2b


the problem with coupling with nhs or cnbr sepharose is that it doesn't force proper orientation of the antibody and your affinity gel will not be as efficient as possible. i've had great success with the pierce protein a antibody orientation kit (a bit pricey but worth it for me). if protein a doesn't work well then you can try the protein g antibody orientation kit. check the manuals (links on the pages for the products) to determine which might be better for you. they use dss but the system is well defined.




Nhs activation of sepharose 2b



A radioimmunoassay (the C1-inhibitor-complex assay, INCA) is described for the detection of complexes that are composed of at least C1s and C1-inhibitor. This INCA is based on demonstrating that C1s and C1-inhibitor (C1-In) are linked: after an incubation with anti-C1s-Sepharose, bound C1sC1-In complexes are detected by 125I-anti-C1-In. C1sC1-In complexes were prepared by the addition of a slight excess of C1s to normal human serum (NHS). As little as 2 ng C1-In bound to C1s was detected. Additional free C1s in serum hardly influenced the detection of C1sC1-In complexes. Complexes presumably composed of C1rC1s(C1-In)2 were generated by the addition of aggregated IgG to NHS. This generation was inhibited by lowering the temperature to 0 degrees C, and by EDTA, and depended on the concentration of aggregated IgG. These complexes had a sedimentation value of approximately 9S. Complexes of C1s and C1-In were also generated in NHS by the addition of DNP-albumin and protein A, but not by zymosan. The INCA was applied to blood samples from normal donors and patients. Sixteen out of 19 samples from patients with acute glomerulonephritis contained increased amounts of C1rC1s(C1-In)2 complexes as compared with the amounts in blood samples from normal donors. The INCA provides a useful tool to assess the activation of C1 in the presence of C1-In, both in vitro and in vivo.


First, EDC activates carboxyl groups and forms an amine reactive O-acylisourea intermediate that spontaneously reacts with primary amines to form an amide bond and an isourea by-product. The O-acylisourea intermediate is unstable in aqueous solutions and failure to react with an amine will cause hydrolysis of the intermediate, regeneration of the carboxyls, and the release of an N-substituted urea. Therefore, it is necessary to quench the EDC activation reaction with a thiol-containing compound like 2-mercaptoethanol. EDC couples NHS to carboxyls, which forms an NHS ester that is considerably more stable than the O-acylisourea intermediate and allows for efficient conjugation to primary amines at physiologic pH.


The SARS-CoV accessory protein 7a is a type I membrane protein with an extracellular domain of 81 amino acid residues. It is described to be expressed during infection and to be a component of the virus particle surface. In this study, we demonstrate that protein 7a binds directly and specifically to human lymphocyte function-associated antigen 1 (LFA-1) on the cell surface of Jurkat cells. The binding is increased upon artificial cell activation with phorbol ester. These observations are confirmed by direct in vitro binding of recombinant protein 7a to the wild type and mutant K287C/K294C I domain showing that the I domain is the 7a binding site in the αL chain of LFA-1. Consequences of the LFA-1 interaction with 7a are discussed. In particular, our data suggest LFA-1 to be an attachment factor or the receptor for SARS-CoV on human leukocytes.


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