A novel peptide isolated from the leaves of Gymnema sylvestre--I. Characterization and its suppressive effect on the neural responses to sweet taste stimuli in the rat.

1. A new substance that suppressed selectively the neural responses of the rat to sweet taste stimuli was isolated from the leaves of Gymnema sylvestre. 2. The substance was proved to be a peptide consisting of 35 amino acids and having a molecular weight of about 4,000. 3. The inhibitory effect on the sweet responses appeared after treating the tongue surface with the peptide at a concentration of more than 1 x 10(-6) M.     

A convenient S-2-aminoethylation of cysteinyl residues in reduced proteins

The cysteinyl residues in proteins had been S-2-aminoethylated with ethylenimine quantitatively. However, ethylenimine is now listed as a carcinogen and is no longer commercially available. A method of converting cysteinyl residues to S-2-aminoethyl derivatives quantitatively using 2-bromoethylamine under mild conditions was developed here.     

Immunohistochemical localization of Met-enkephalin, Met-enkephalin-Arg6-Gly7-Leu8, Met-enkephalin-Arg6-Phe7 and Leu-enkephalin in human adrenal medulla and pheochromocytomas

Immunohistochemical localization of Met-enkephalin, Met-enkephalin-Arg6-Gly7-Leu8, Met-enkephalin-Arg6-Phe7 and Leu-enkephalin was studied in human adrenal medulla and pheochromocytomas at the light and electron microscopic levels. Both adrenal medulla and pheochromocytomas (4 adrenal, 1 extra-adrenal) showed scattered or clustered cells which contained all of the above peptides and suggested the production of proenkephalin A. The presence of these peptides predominantly in the secretory granules suggested that proenkephalin A is processed to final products mainly in the secretory granules. The localization of Met-enkephalin-Arg6-Gly7-Leu8 and Met-enkephalin-Arg6-Phe7 in cisternae of rough endoplasmic reticula indicated their actual production in pheochromocytomas.     

Improving enzyme characteristics by gene shuffling; application to β-glucosidase

The genes of family 3 β-glucosidase enzymes consist of five distinct regions; the N-terminal residues, an N-terminal catalytic domain, a nonhomologous region, a C-terminal domain of unknown function and the C-terminal residues. The β-glucosidase genes derived from Cellvibrio gilvus (CG) and Agrobacterium tumefaciens (AT) have been subjected to gene deletion, truncation and shuffling. The folding information was found to be distributed unevenly across the different regions based on the gene manipulation results. Chimeric enzymes with improved enzyme characteristics were obtained only by gene shuffling at the C-terminal domain.     

Changes in neutrophil functions during a 10‐month soccer season and their effects on the physical condition of professional Japanese soccer players

We examined changes in neutrophil function of soccer players over a 10‐month period and determined its effectiveness as an index for athlete physical condition. Subjects included 21 male professional Japanese soccer players. Data on body composition, myogenic enzymes and neutrophil function were obtained before and after 2 h of training at 3 investigation points: one week before opening season, at season mid‐point, and one week before the last game of the season. As a result, change ratios of myogenic enzyme levels before and after the 2‐hr training session at the third investigation point were significantly higher compared to the two other points. Reactive oxygen species production and phagocytic activity significantly increased after 2‐hr training session at point 1, although the extent of the increase became smaller over time and ROS production capability decreased significantly by point 3 assessment. Fatigue, especially muscle fatigue, chronically accumulated along with a gradual decrease in neutrophil immune function over the 10‐month season. Therefore, determination of neutrophil function can be used as a useful index to assess and understand an athlete's physical condition. Copyright © 2012 John Wiley & Sons, Ltd.     

Magnetic circular dichroism and spin equilibrium of methemoglobin and its subunits

The intensity of the Soret magnetic circular dichroism (MCD) spectra of various complexes of methemoglobin subunits (α⁺ and β⁺) as well as methemoglobin (metHb A) was correlated well with the spin states of ferric heme. Upon the subunit association, spin state transition toward higher spin was observed only in high spin derivatives and the changes in spin state were due to mainly those of β⁺ chains. The effect of an allostric effector, inositol hexaphosphate (IHP), on the MCD spectra of metHb A derivatives was observed much significantly for high spin forms than low spin ones.     

Binding of calcium to lysozyme and its derivatives

Bindings of calcium to lysozyme and its derivatives were studied by UV difference spectroscopy at various pH's. The binding constant was ca. 40 m-1 at around neutral pH. The binding caused proton release from lysozyme and did not inhibit the binding of tri-N-acetylglucosamine to lysozyme. In the presence of 0.2 M Ca2+, lysozyme showed 26% of the activity of the free enzyme toward hexa-N-acetylglucosamine but the cleavage pattern was similar to that of the free enzyme. Thus, calcium was predicted to bind near the catalytic carboxyls to cause inhibition of lysozyme activity. It was found from the results of protease digestion that calcium binding shifted the native-denatured transition in lysozyme toward the native state.