Two non-canonical amino acids (ncAAs) with bio-orthogonal reactive groups, namely, p-azido-L-phenylalanine (p-AzF) and p-propargyloxy-L-phenylalanine (p-PaF), were genetically inserted into an aldo-keto reductase (AKR) alcohol dehydrogenase (ADH), respectively, at...

The title compound, C(51)H(78)N(4)O(12), is a derivative of rapamycin, a triene macrolide anti-biotic mol-ecule isolated from Streptomyces hygroscopicus. The macrocyclic ring structure has 15 chiral centres, with one of the substituent hy-droxy groups giving an intra-molecular hydrogen bond to a ketone O-atom acceptor. The mol-ecules also form inter-molecular hy-droxy-ketone O-H⋯O hydrogen-bond...

6-Azidoflavins have been bound to the apoproteins of five representative flavoproteins and their properties, before and after light irradiation, compared with those of the same proteins containing the appropriate 6-aminoflavin. In the dark the 6-azidoflavoproteins are quite stable, except for L-lactate oxidase, where spontaneous conversion to the 6-amino-FMN enzyme occurs slowly at pH 7. 6-Azid...

A series of novel aliphatic polyesters with azido functional groups were synthesized via the direct lipase-catalyzed polycondensation of dialkyl diester, diol and 2-azido-1,3-propanediol (azido glycerol) using immobilized lipase B from Candida antarctica (CALB). The effects of polymerization conditions including reaction time, temperature, enzyme amount, substrates and monomer feed ratio on the...

To facilitate structural and dynamic studies of G protein-coupled receptor (GPCR) signaling complexes, new approaches are required to introduce informative probes or labels into expressed receptors that do not perturb receptor function. We used amber codon suppression technology to genetically-encode the unnatural amino acid, p-azido-L-phenylalanine (azF) at various targeted positions in GPCRs ...

Mechanisms that have been proposed for peroxidase-catalyzed iodination require the utilization of 1 mol of H2O2 for organic binding of 1 mol of iodide. When we measured the stoichiometry of this reaction using thyroid peroxidase or lactoperoxidase at pH 7.0, we consistently obtained a ratio less than 1.0. This was shown to be attributable to catalase-like activity of these enzymes, resulting in...

The active site of antibody directed against the negatively charged p-azobenzenearsonic acid group has been shown to contain an iodine-reactive residue. The first evidence was provided by Pressman and Sternberger (1)) who demonstrated that iodination destroys the precipitating capacity of this antibody and that the loss can be prevented by the prior addition of the homologous hapten. Subsequent...