Design and synthesis of biotin- or alkyne-conjugated photoaffinity probes for studying the target molecules of PD 404182

To investigate the mechanism of action of the potent antiviral compound PD 404182, three novel photoaffinity probes equipped with a biotin or alkyne indicator were designed and synthesized based on previous structure–activity relationship studies. These probes retained the potent anti-HIV activity of the original pyrimidobenzothiazine derivatives. In photoaffinity labeling studies using HIV-1-infected H9 cells (H9IIIB), eight potential proteins were observed to bind PD 404182.     

Design and synthesis of a series of α-benzyl phenylpropanoic acid-type peroxisome proliferator-activated receptor (PPAR) gamma partial agonists with improved aqueous solubility

In the continuing study directed toward the development of peroxisome proliferator-activated receptor gamma (hPPARγ) agonist, we attempted to improve the water solubility of our previously developed hPPARγ-selective agonist 3, which is insufficiently soluble for practical use, by employing two strategies: introducing substituents to reduce its molecular planarity and decreasing its hydrophobicity via replacement of the adamantyl group with a heteroaromatic ring. The first approach proved ineffective, but the second was productive. Here, we report the design and synthesis of a series of α-benzyl phenylpropanoic acid-type hPPARγ partial agonists with improved aqueous solubility. Among them, we selected (R)-7j, which activates hPPARγ to the extent of about 65% of the maximum observed with a full agonist, for further evaluation. The ligand-binding mode and the reason for the partial-agonistic activity are discussed based on X-ray-determined structure of the complex of hPPARγ ligand-binding domain (LBD) and (R)-7j with previously reported ligand-LDB structures. Preliminal apoptotic effect of (R)-7j against human scirrhous gastric cancer cell line OCUM-2MD3 is also described.     

Synthesis of Several Fructo-oligosaccharides by Asparagus Fructosyltransferases

Nine fructo-oligosaccharides, synthesized in vitro from sucrose by an enzyme preparation from asparagus roots, were isolated and their structures were elucidated to be 1^F (1-β-fructofuranosyl)_n sucrose [n = 1 (1-kestose), 2 (nystose) and 3], 6^G (1-β-fructofuranosyl)_n sucrose [n=1 (neokestose), 2 and 3] and 1^F (1-β-fructofuranosyl)_m-6^G (1-β-fructofuranosyl)_n sucrose [m=1, n=1; m=2, n =1; and m =1, n=2]. These saccharides are all known to occur naturally in asparagus roots, but 6^G (1-β-fructofuranosyl)₃ sucrose and 1^F (1-β-fructofuranosyl)_m-6^G-(1-β-fructofuranosyl)_n sucrose (m=1, n =1; and m=1, n=2) were the first saccharides enzymatically synthesized in vitro. Also three types of fructosyltransferases were presumed to be involved in the biosynthesis of these oligosaccharides in asparagus roots.     

Effect of Gamma Irradiation on the Amino Acid of Potatoes

The free amino acids of potatoes irradiated with the doses of 7,000, 15,000 and 30,000 rad were determined by ion-exchange chromatography.

After 15 days storage following irradiation, it was shown that the concentration of asparatic acid, proline and aliphatic amino acids increased with increasing irradiation doses, while that of basic amino acids and glutamic acid especially decreased. However, after 105 days of storage, the similarity of the free amino acid content of irradiated potatoes to that of non-irradiated and non-stored potatoes was observed.

On the concentration of protein-bound amino acids, there were no significant differences between non-irradiated and 15,000 rad irradiated potatoes.     

Antimicrobial Activity of Kumazasa (Sasa albo-marginata)

The organic solvent extract of Kumazasa leaves (Sasa albo-marginata) showed antimicrobial activity against bacteria, fungi and yeast. Kumazasa at a concentration of 0.2-1.0% showed stronger antimicrobial activity than potassium sorbate or sodium benzoate at the same concentration. Both acidic and phenolic fractions of the extract showed strong antimicrobial activity. Thirty acidic and phenolic compounds were identified by GC and GC-MS analysis. Acetic, propionic, benzoic, phenylacetic, salicylic, 3-hydroxybenzoic and o-anisic acids, and guaiacol, phenol, 4-ethylphenol, xylenol and 4-vinylphenol were the main components. It was estimated that these components play an important role in the formation of the antimicrobial activity of Kumazasa extract.     

Glutamyl Oligopeptides as Factors Responsible for Tastes of a Proteinase-modified Soybean Protein

AK-toxin I, a host-specific toxin to Japanese pear (Pyrus serotina), was synthesized as its methyl ester from three precursor fragments: conjugated diene-carboxylic acid, chiral epoxyalcohol and β-methylphenylalanine. The epoxyalcohol fragment was derived from D-fructose, in which effective homologation of the hemiacetal carbon to alkyne by using dimethyl 1-diazo-2-oxopropylphosphonate was the key reaction. The diene-carboxylic acid fragment was prepared by repeated Wittig reactions, and was combined with the epoxyalcohol fragment by the Stille reaction. Esterification of the combined product with the stereochemically-pure β-methylphenylalanine fragment afforded the target compound. This method was used to prepare the methyl ester of tritium-labeled AK-toxin I with a specific radioactivity of 213 GBq/mmol.     

Studies on Proteolysis in Stored Muscle

Changes in the nonprotein nitrogenous compounds produced from rabbit skeletal muscle (L. dorsi) by proteolysis were investigated.

The value of trichloroacetic acid soluble nitrogen, ninhydrin positive materials and phenol reagent positive materials increased during storage at low and high temperature. Changes in bound and free amino acid contents produced by proteolysis during storage were assayed by amino acid analyzer. Most of free amino acids except taurine increased remarkably. Amounts of asparatic acid, glutamic acid, glycine, β-alanine and histidine were increased after hydrolysis as compared with those before hydrolysis.

By using five kinds of Dowex 50 columns, changes in the distributive patterns of the nonprotein nitrogenous compounds were also studied.     

Studies on Egg White Proteins

Four components of ovomucoid were digested exhaustively and four kinds of glycopeptide corresponding to the four components were separated by gel filtration. Each glycopeptide was shown to be homogenious by paper chromatography and paper electrophoresis. Molar ratios of carbohydrate components of these glycopeptides varied to some extent but the amino acid compositions of these glycopeptides were essentially identical with each other with the exception of alanine. Aspartic acid and threonine were predominant amino acids in the all glycopeptides. It is most likely that the modes of linkages between polysaccharide and protein in individual ovomucoid I, II, III and IV are essentially the same, and that the carbohydrate moiety is linked to the protein via asparaginyl residue or the hydroxyl group of threonine, although the possibility of the linkages to glutamine and serine can not be excluded.