Catalytic antibodies induced by a zwitterionic hapten

A zwitterionic hapten 4 featuring both positively and negatively charged functional groups was designed and synthesized with the goal of generating catalytic antibodies for the hydrolysis of ester 6 and amide 7. Of the 36 monoclonal antibodies specific to BSA-4 (bovine serum albumin) that were isolated, six accelerated the hydrolysis of 6. Two catalytic antibodies with distinctively different and representative kinetic behaviors were selected for detailed kinetic studies. Whereas H8-2-6F11 showed burst kinetic behavior, which can be attributed to the formation of an acyl intermediate, H8-1-2D5 did not, but it did exhibit high multiple turnover activity. The rate of hydrolysis of 6 catalyzed by H8-1-2D5 followed Michaelis-Menten kinetics; the apparent values of the Michaelis-Menten constant Km and the catalytic constant kcat were 488 microM and 3.5 min(-1), respectively. The catalytic rate enhancement (kcat/kun) observed for H8-1-2D5 was 1.3 x 10(5), which is approximately two orders of magnitude greater than those for monofunctional haptens. Thus H8-1-2D5 compares well in catalytic activity with antibodies isolated by a related approach called heterologous immunization.     

Photochemical modification of diamond films: introduction of perfluorooctyl functional groups on their surface

Photolysis of perfluoroazooctane with diamond films led the chemical modification of the surface to introduce perfluorooctyl functional groups, confirmed by means of Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and time-of-flight secondary ion mass spectrometry measurements. Diamond films modified with fluorine moieties showed improved frictional property and reduction of surface energy, as evaluated by contact angle to water, compared with a pristine diamond film. The contact angle and friction coefficient of chemically modified diamond film are 118 degrees and 0.1, respectively. The results of the value of the contact angle depending on irradiation times are consistent with those of the F/C ratio of fluorinated diamond films by monitoring with XPS.     

Mössbauer spectroscopic study of gamma-ray irradiated potassium phosphate glasses

A Mössbauer spectroscopic study was performed to investigate the effect of γ-ray irradiation on the formation of non-bridging oxygens in the potassium phosphate glasses denoted by the formula x K₂O · (100 ? x)P₂O₅ · 7 Fe₂O₃ (0 ? x ? 50 mol.%). Mössbauer spectra for these glass samples consisted of two kinds of doublets due to Fe²⁺ and Fe³⁺ ions of octahedral symmetries. Only small changes occurred in the Mössbauer parameters as a result of irradiation at room temperature in a dry nitrogen atmosphere, except for the decrease in the absorption area for the Fe²⁺ ions. The decrease in the absorption area was attributed to the electron transfer from the Fe²⁺ ions to the neighboring oxygens. Thermal annealing experiments for a few non-irradiated glass samples indicated that the decrease in the absorption area was confirmed to be due to γ-rays rather than heating during the irradiation.     

Triple helicate constructed by covalent bondings: crystal structure and effective synthesis based on propeller-like substructures

A triple helicate, having a macrocyclic aromatic amide structure, was synthesized in high yield because of a preorganized component of the tertiary benzenetrianilide moieties in a propeller-like syn conformation at both ends. The helicity was derived from tilted T-shaped aromatic-aromatic (CH-pi) interactions between each of the N-phenyl rings. [structure: see text]     

Spectrophotometric determination of urinary protein with o-sulfophenylfluorone-metal complex.

A simple and sensitive spectrophotometric method for the determination of human serum albumin (HSA) was established based on the ternary complex-formation reaction of HSA with o-sulfophenylfluorone (SPF) as a xanthene dye and metal ion (niobium(V) and bismuth(III)) in the presence of a dispersion agent. This new method enabled the determination of HSA in the range of 1 - 15 microg/ml HSA by measuring the difference of the absorbance at 530 nm between HSA-SPF-metal ion and SPF-metal ion solutions. In the determination of HSA, this method is about 2-times more sensitive than the Pyrogallol Red-molybdenum(VI) method (PR method), which accounts for more than 80% of the quantification methods for urinary protein assays in Japan. There was no significant difference between the results obtained by the present method and the PR method for human urine samples. The binding process between the SPF-metal complex and HSA was studied by determining the binding parameters and the thermodynamic parameters.     

Isolation and characterization of N-alkyl-N- (hydroxymethyl)nitrosamines from N-alkyl-N- (hydroperoxymethyl)nitrosamines by deoxygenation

N-Alkyl-N- (hydroxymethyl)nitrosamines, postulated intermediates in the metabolic activation of carcinogenic nitrosamines, were prepared by deoxygenation of the corresponding hydroperoxymethyl nitrosamines and characterized.