Structurally well‐defined heterogeneous N‐glycoclusters are prepared on albumin via a double click procedure. The number of glycan molecules present, in addition to the spatial arrangement of glycans ...in the heterogeneous glycoclusters, plays an important role in the in vivo kinetics and organ‐selective accumulation through glycan pattern recognition mechanisms.
We show the value of mass-momentum diagrams for analyzing collision problems in classical mechanics in one dimension. Collisions are characterized by the coefficient of restitution and the momenta of ...the interacting particles both before and after the collision. All those quantities are presented in the mass-momentum diagrams without the need to do any calculations. We also show that the same diagrams can be used to investigate collisions with respect to the center-of-mass system. In this case, also, we do not need to do any calculations to obtain the momentum. Since we give an alternative way of looking at collisions in classical mechanics, this article is aimed at undergraduate-level students.
Advanced glycation end products (AGEs) are associated with various diseases, especially during aging and the development of diabetes and uremia. To better understand these biological processes, ...investigation of the
in vivo
kinetics of AGEs,
i.e.
, analysis of trafficking and clearance properties, was carried out by molecular imaging. Following the preparation of Cy7.5-labeled AGE-albumin and intravenous injection in BALB/cA-nu/nu mice, noninvasive fluorescence kinetics analysis was performed.
In vivo
imaging and fluorescence microscopy analysis revealed that non-enzymatic AGEs were smoothly captured by scavenger cells in the liver,
i.e.
, Kupffer and other sinusoidal cells, but were unable to be properly cleared from the body. Overall, these results highlight an important link between AGEs and various disorders associated with them, which may serve as a platform for future research to better understand the processes and mechanisms of these disorders.
Molecular imaging visualized significantly reduced clearance of AGE-albumin.
After the leading reports of copper-catalyzed click reaction by Sharpless and co-workers, many chemical conjugation reactions on protein or cell surface have been developed, and they impacted on the ...various chemical biology research. In the field of glycochemical biology, the cell-surface fluorescence labeling through the strain-promoted click reaction has been developed by Bertozzi, and then extensively studied and optimized by Boons and the other researchers; the method could successfully visualize the glycan expression and dynamics on and in live cells (Science (2008), 320, 664-667) . Davis, on the other hand, has achieved conjugating the glycan recognition property on the enzymatic activity of protein, by site-selectively introducing it at the specific position on the protein (Nature (2007), 446, 1105-1109) . The next challenges for glycochemists are to conjugate the glycans in living systems at any desired time and place, i.e., in cells or even on specific organs, and to effect the glycan functions at our will.
A diaryliodonium salt-based strategy enabled the first systematic synthesis of rarely accessible N-alkoxyindolines. Mechanistic analyses suggested that the reaction likely involves reductive ...elimination of iodobenzene from iodaoxazepine via a four-membered transition state, followed by Meisenheimer rearrangement. Substrates with N-carbamate protection afforded indole in a manner similar to that of the Ishikawa indole synthesis. Preinstallation of a stannyl group as an iodonium salt precursor greatly expanded the substrate scope, and further mechanistic insights are discussed.
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