6 research outputs found
Synthetic Assembly of Bifluorescence-Labeled Glycopolymers as Substrates for Assaying α-Amylase by Resonance Energy Transfer
To meet the need for a convenient substrate for sensitive
and continuous
assay for α-amylase, we developed a fluorescence resonance energy
transfer (FRET)-based polymer substrate. Radical copolymerization
of FRET-component monomers in different ratios of fluorogenic donor
and acceptor was utilized to prepare such polymers. A glycomonomer
as a fluorogenic donor was derived from naphthylmethylated maltotetraose,
and a dansyl derivative monomer was used as an acceptor. Their mixture
and acryl amide were copolymerized in a typical radical polymerization
to yield a bifluorescence-labeled polymer in good yield. All of the
polymers showed effective FRET and were used for the continuous assay
of human salivary α-amylase. The time course of α-amylase
reactions led to the apparent kinetic parameters of <i>K</i><sub>m</sub> = 4 μM and <i>V</i><sub>max</sub> =
0.29 nmol/min. The results strongly suggested that FRET-sensitive
polymers are conveniently accessible and applicable for the sensitive
determination of biochemical events
Preparation of <i>N</i>‑Linked-Type GlcNAc Monomers for Glycopolymers and Binding Specificity for Lectin
Glycomonomers having N-glycosidic linkages
were
prepared from a known glycosyl amine, N-acetyl-d-glucosamine (GlcNAc). Radical polymerization of the glycomonomers
gave a series of glycopolymers displaying various sugar densities,
which were models of the core structure of Asn-linked-type glycoproteins.
In addition, fluorometric analyses of wheat germ agglutinin (WGA)
against the glycopolymers were carried out, and the results showed
unique binding specificities on the basis of flexibility of sugar
moieties
Synthesis and Structural Revision of a Brominated Sesquiterpenoid, Aldingenin C
This
paper describes a short step synthesis of the proposed structure
for aldingenin C from <i>trans</i>-limonene oxide. The tetrahydropyran-fused
2-oxabicyclo[3.2.2]nonane skeleton as the structural feature was constructed
by an intramolecular epoxide-opening reaction and a brominative cyclization.
The spectral data of the synthetic compound did not match those of
the natural product reported. Re-examination of the reported NMR data
using new CAST/CNMR Structure Elucidator suggests that the structure
of aldingenin C should be revised to that of known caespitol
Triphenylphosphinecarboxamide: An Effective Reagent for the Reduction of Azides and Its Application to Nucleic Acid Detection
A series of triphenylphosphinecarboxamide
(TPPc) derivatives were
designed and synthesized as alternative reagents to triphenylphosphine
for the facile reduction of azides. The TPPc derivatives performed
as efficient reducing agents for the synthesis of primary amines without
the need for an additional hydrolysis procedure. The TPPc derivatives
were also applied to nucleic acid sensing using a RhAz-oligonucleotide
conjugate in a DNA-templated fluorogenic reaction
Preparation of a Water-Soluble Glycopolymer Bearing Porphyrin Skeletons and Its Biological Properties
A known tetraphenyl porphyrin (TPP) having an amino functional
group [5-(4-aminophenyl)-10,15,20-(triphenyl)porphyrin] was converted
into the corresponding monomer by means of condensation with acryloyl
chloride. Simple radical polymerization of the porphyrin monomer and
a glycosyl monomer in the presence of acrylamide as a regulator monomer
in order to avoid steric interference gave a water-soluble glycopolymer
bearing porphyrin moieties. Spectroscopic analyses suggested incorporation
of porphyrin moieties in the glycopolymer. The physical properties
of the water-soluble glycopolymer bearing porphyrin moieties were
examined in aqueous media, and the results also indicated the incorporation
of TPP moieties in the polymer. Uptake of the polymer into HeLa cells
was observed, and the cytotoxicity of the polymer was confirmed by
microscopic analyses. The glycopolymer bearing porphyrin moieties
is promising not only for photodynamic therapy but also as an anti-cancer
reagent
Synthesis and Influenza Virus Inhibitory Activities of Carbosilane Dendrimers Peripherally Functionalized with Hemagglutinin-Binding Peptide
A series
of carbosilane dendrimers uniformly functionalized with
hemagglutinin (HA) binding peptide (sialic acid-mimic peptide, Ala-Arg-Leu-Pro-Arg)
was systematically synthesized, and their anti-influenza virus activity
was evaluated. The carbosilane-based peptide dendrimers, unlike sialylated
dendrimers, cannot be digested by virus neuraminidases. The peptide
dendrimers exhibited intriguing biological activities depending on
the form of their core frame, with a dumbbell-type peptide dendrimer
showing particularly strong inhibitory activities against two human
influenza viruses, A/PR/8/34 (H1N1) and A/Aichi/2/68 (H3N2). The IC<sub>50</sub> values of the dumbbell-type peptide dendrimer for both strains
were 0.60 μM, the highest activity among the HA-binding peptide
derivatives. The results suggest that a dumbbell-shaped carbosilane
dendrimer is the most suitable core scaffold for HA-binding peptide
dendrimers