We present a novel use for channel structures in microfluidic devices, whereby two two-phase emulsions, one created on-chip, the other off-chip, are rapidly mixed with each other in order to allow for the coalescence of one emulsion with the other. This approach has been motivated by the difficulty in introducing aqueous cross linking agents into droplets by utilising conventional approaches. T...

Like many other cell surface receptors, the CD95 (APO-1/Fas) molecule needs to be cross-linked by its physiological ligand or by immobilized or multimeric antibodies to mediate biological activity, that is, induction of apoptotic cell death. Monomeric CD95 antibodies of the IgG2a or IgG1 subtype block rather than induce apoptosis. We report here that such antibodies, hybridized to a second anti...

We have developed an artificial protein scaffold, herewith called a protein vector, which allows linking of an in-vitro synthesised protein to the nucleic acid which encodes it through the process of self-assembly. This protein vector enables the direct physical linkage between a functional protein and its genetic code. The principle is demonstrated using a streptavidin-based protein vector (SA...

We developed an automated diagnostic system for the detection of virus-specific immunoglobulin Gs (IgGs) that was based on a microarray platform. We compared efficacies of our automated system with conventional enzyme immunoassays (EIAs). Viruses were immobilized to microarrays using a radical cross-linking reaction that was induced by photo-irradiation. A new photoreactive polymer containing p...

RNA-dependent protein kinase (PKR) is an interferon-induced, RNA-activated enzyme that phosphorylates and inhibits the function of the translation initiation factor eIF-2. PKR is activated in vitro by binding RNA molecules with extensive duplex structure. To further define the nature of the RNA regulation of PKR, we have prepared and characterized site-specifically modified proteins consisting ...

The electrogenic sodium bicarbonate cotransporter NBCe1-A mediates the basolateral absorption of sodium and bicarbonate in the proximal tubule. In this study the oligomeric state and minimal functional unit of NBCe1-A were investigated. Wild-type (wt) NBCe1-A isolated from mouse kidney or heterologously expressed in HEK293 cells was predominantly in a dimeric state as was shown using fluorescen...

Incubation of maize (Zea mays) leaf NADP-malic enzyme with monofunctional and bifunctional N-substituted maleimides results in an irreversible inactivation of the enzyme. Inactivation by the monofunctional reagents, N-ethylmaleimide (NEM) and N-phenylmaleimide, followed pseudo-first-order kinetics. The maximum inactivation rate constant for phenylmaleimide was 10-fold higher than that for NEM, ...

Chemical crosslinking mediated by short bifunctional reagents has been widely used for determining physical relationships among polypeptides in multisubunit proteins, but less often for functional studies. Here we introduce the approach of tethering polypeptides by using bifunctional reagents containing a lengthy, flexible PEG linker as a form of crosslinking especially suited to functional ana...