Reversible protein biotinylation is readily affected via conjugation with a bromomaleimide-based reagent followed by reductive cleavage. The intermediate biotinylated protein constructs are stable at physiological temperature and pH 8.0. Quantitative reversibility is elegantly delivered under mild conditions of using a stoichiometric amount of a bis-thiol, thus providing an approach that will b...

An operationally simple, mild, redox-neutral method for the photoredox alkylation of imines is reported. Utilizing an inexpensive organic photoredox catalyst, alkyl radicals are readily generated from the single-electron oxidation of ammonium alkyl bis(catecholato)silicates and are subsequently engaged in a C-C bond-forming reaction with imines. The process is highly selective, metal-free, and ...

H. Khalili, S. Brocchini, P. Khaw University College London Purpose We have recently shown that Fab-PEG-Fab (FpF) molecules are antibody (MAb) mimetics [1]. Site-specific conjugation of the Fab in the region where it is naturally bound to the hinge in a MAb to each terminus of a linear PEG molecule yields the FpF. Since the PEG in FpFs appears to allow good avidity of the Fabs, and better stabi...

The inactivation of beef liver porphobilinogen synthase by the alkylating agents iodoacetate and iodoacetamide has been investigated. The synthase can be inactivated by these reagents only if the enzyme has been activated initially by sulfhydryl reducing agents. Inactivation by both iodoacetate and iodoacetamide was the result of modification of cysteinyl residues. A plot of the incorporation o...

Reaction of the antitumor agent leinamycin with cellular thiols results in conversion of the natural product to a DNA-alkylating episulfonium alkylating agent via an intriguing sequence of chemical reactions. To establish whether the chemistry first seen in leinamycin represents a general motif that can function in various molecular frameworks, construction of greatly simplified analogues conta...

Due to the unique optical properties like high brightness and narrow emission bands of Quantum dots, it is used as simple fluorescence materials in bio-imaging, immunoassays, microarrays, and other applications. To easy invistigate cell lines that overexpressed somtostatin receptors, somatostatin (SST) was conjugated with Quantum dots carrying PEG amine (Qdots-PEG-NH2). The conjugation of SST t...

Due to the unique optical properties like high brightness and narrow emission bands of Quantum dots, it is used as simple fluorescence materials in bio-imaging, immunoassays, microarrays, and other applications. To easy invistigate cell lines that overexpressed somtostatin receptors, somatostatin (SST) was conjugated with Quantum dots carrying PEG amine (Qdots-PEG-NH2). The conjugation of SST t...

A simple two-step protocol for modification of atomic force microscopy (AFM) tip and substrate by using a "click reaction" has been developed. The modified tip and substrate would be applied to detect trace amounts of ricin by using atomic force microscopy. A key feature of the approach is the use of a PEG (polyethylene glycol) derivative functionalized with one thiol and one azide ending group...

SUMMARY The protective action of mercaptoalkylamines has been examined. Anticipated protection against HN2 has been observed, l-mercapto-2-aminobutane being slightly more effective than cysteamine. Protection failed in the case of L-phenylalanine mustard and chloroquine mustard, but significant post-protection was obtained with Cytoxan. Results obtained with various combinations of intraperiton...

Many clinically used protein therapeutics are modified to increase their efficacy. Example modifications include the conjugation of cytotoxic drugs to monoclonal antibodies or poly(ethylene glycol) (PEG) to proteins and peptides. Monothiol-specific conjugation can be efficient and is often accomplished using maleimide-based reagents. However, maleimide derived conjugates are known to be suscept...