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Biomedical subjects

N Ise

Publications and source records attributed to N Ise.

At least 37 records · Page 2Linked to original sources
PubMed1989

Direct examination of chemical kinetic laws by visual imagery. IV. Association processes between antigen- and fragmented antibody carrying fluorescent latex particles.

The binary association process was further examined by direct visual observation using a fluorescence microscope connected to an image-processing system and by a spectrophotometric method. In the present paper, we used human serum albumin (HSA)- and fragmented anti-HSA antibody-carrying fluorescent latex particles in order to attain higher sensitivities and exclude complexities that might be caused by dissociation of the association product. The rate constant of the binary association process was estimated to be 6.0 x 10(8) M-1 s-1 at 30 degrees C and pH 7.6. The activation parameters of the association process were evaluated. The effects of pH and viscosity of the suspension on the association process were also examined.

Antigen-Antibody Complex↗
PubMed1988

Mutual recognition between polymerized liposomes: enzyme and enzyme inhibitor system.

In order to examine the usefulness of polymerized liposomes as a model for cell membranes, a mutual recognition phenomenon between different liposomes on which complementary ligands were attached was examined. We used trypsin- and soybean trypsin inhibitor (STI)-carrying polymerized liposomes to attain high sensitivities. The STI which was immobilized on the polymerized mono-dienoylphosphatidylcholine liposome showed a definite inhibitory effect on the catalytic activity of the trypsin which was immobilized on another polymerized liposome, whereas the inhibitory effect of the STI which was immobilized on the di-dienoylphosphatidylcholine liposome was much smaller than that of the mono-dienoylphosphatidylcholine system because of the larger rigity of the di-dienoylphosphatidylcholine liposome. These results suggest that the mutual recognition between complementary ligands can be realized by using polymerized liposomes with a physical stability and moderate deformability as their carriers.

Cell Communication↗
PubMed1988

Functional properties of proteins immobilized on albumin microspheres.

Bovine serum albumin (BSA) microspheres with an average diameter of 12.5 micron were prepared by crosslinking of BSA molecules with glutaraldehyde in the presence of polymethylmethacrylate dissolved in chloroform-toluene. Trypsin and anti-human IgG antibody were immobilized onto their surfaces by the glutaraldehyde-activation method. The catalytic activity and storage stability of the immobilized trypsin were satisfactorily high. The enzyme immunoassay (EIA) method using BSA-microspheres as a solid phase has a high sensitivity (the minimum concentration of detectable antigen in the sample: 0.2 ng/ml) and a wide concentration range (final concentration 0.027-3000 ng/ml) for the detection of human IgG.

Enzyme-Linked Immunosorbent Assay↗
PubMed1987

Pulse injection analysis of the binding of serum proteins to porous polymer gels modified with formyl groups.

Highly porous spherical polymer gels were modified with formyl groups by a modified Friedel-Crafts reaction and the interaction of serum proteins with the modified gels were examined by pulse injection analysis. The introduction of formyl groups into the polymer greatly increases its protein-binding capacity, and the protein bound to the gel is not eluted by washing with acid, alkali or urea solution. The effects of temperature and the percentage of formyl group substitution on the binding capacity indicate that the binding process can be interpreted as initial approach of the protein to the polymer surface, caused by the hydrophobic interaction, followed by formation of a stable Schiff base between the polymer gel and the protein. Theoretical treatment of the elution behaviour of the protein from the polymer-packed column is also examined, with the assumption that there are three kinds of binding site in the polymer gel: surface, macropore and micropore regions. These polymers are shown to be useful for the removal of proteins from biological samples in clinical assays using immobilized enzymes.

Animals↗
PubMed1982

Pressure dependence of trypsin-catalyzed hydrolyses of specific substrates.

The effects of pressure on the trypsin-catalyzed hydrolyzed hydrolyses of three specific substrates, N-benzoyl-L-arginine ethyl ester (BzArgOEt), amide (BzArgNH2) and p-nitroanilide (BzArgNA), have been examined. The volume of the activation (delta V++) for kcat was -2.4 ml/mol for BzArgOEt and +3 - +6 ml/mol for BzArgNH2. Because of different rate-determining steps in the steady-state kinetics, the delta V++ value for BzArgOEt would indicate the activation volume of the deacylation step, whereas that for BzArgNH2 the delta V++ for the acylation step. The activation volumes were accounted for in terms of the difference in the mechanisms on the formation and decomposition of the tetrahedral-like intermediates during the acylation and deacylation steps. The delta V values for the formation of BzArgNH2- and thionine-trypsin complexes were several ml/mol, consistent with the fact that the main driving force of the substrate binding to this enzyme is electrostatic interaction, and in contrast to the delta V values of alpha-chymotrypsin complex formation with indole (approximately 0 ml/mol) or 2-furylacryloyl-D-tryptophan methyl ester (approximately 0 ml/mol), for which the hydrophobic interaction is the dominant force of the substrate binding. For the hydrolysis of BzArgNA, which showed a distinct substrate activation at high substrate concentrations, the pressure dependence of the four parameters, ks, Ks, (the catalytic rate and dissociation constant of the normal enzyme-substrate complex, respectively), Kss and Kss (those of the complex activated by the binding of the second substrate molecule), were measured at 1 atm and 1000 atm (25 degrees C). All of the four parameters increased with increase in pressure.

Amides↗
PubMed1982

Specific and non-specific effects of inert anions and cations on the dimerization of alpha-chymotrypsin and the catalytic activities of monomeric and dimeric alpha-chymotrypsins.

The effect of salts on the dimerization and the catalytic activity of dimeric alpha-chymotrypsin (alpha-CT) was investigated. The observed effect was mainly related to the anionic constituent of the salt, and its order depended on the salt concentration. The order of effect of anions on several parameters at [salt] less than 0.02 M was SO4 2-, ClO4-, NO3-, Br-, Cl-, which reflected the electrostatic interaction between the anion and the positively charged surface of alpha-CT. On the other hand, the anion dependence at moderate salt concentrations (0.1-0.2 M) followed the Hofmeister series, SO4 2-, Cl-, Br-, NO3-, ClO4-, which was related to the direct and indirect interactions between the anion and non-charged groups of the protein. The anion order for the dimerization constant of this enzyme, however, was the complete reverse of that generally observed in the aggregation of proteins at high salt concentration (greater than 1 M). This result was accountable for in terms of a specific interaction in the formation of the dimeric enzyme (probably that between the active site of one monomer and Tyr-146 of the other).

Anions↗