Photochemical Colorine Reaction of Sake

Coloring reaction of sake caused by exposure to sun-light was investigated. There is one of the coloring reactions in which deferri-ferrichrysin participate. The reaction was named Reaction I.

Deferri-ferrichrysin, tyrosine, Mn²⁺ and unknown nitrogenous compound named conveniently compound X were essential for Reaction I and citric acid was stimulative.

Compound X was purified by using Amberlite IR 120 (H type) column, active carbon column, silicic acid column and alumina column, and crystallized from methanol-water (1 : 1).

The crystals decomposed at 288~290°C. The ultraviolet and infrared spectra of the compound X were essentially identical with those of authentic kynurenic acid.

From these results the compound X was identified as kynurenic acid.

Since kynurenic acid alone did not cause the color development and riboflavin could be substituted for kynurenic acid in Reaction I, kynurenic acid may act as photosensitizer in Reaction I.     

Applying Proteolytic Enzymes on Soybean

An indole derivative having blue fluorescence was produced in cooked soybean digested at 37°C for 24 hr with an acid proteinase Molsin (optimum pH: 2.8) from Aspergillus saitoi or a usual acid proteinase pepsin (optimum pH: 1.6) from beef stomach. This indole derivative was identical with a condensation product from l-tryptophan and n-hexanal. Based on MS, NMR, IR and UV spectrometry, the condensation product was identified as l-pentyl-2, 3, 4, 9-tetrahydro-lH-pyrido [3, 4-b]-indole-3-carboxylic acid [trivial name: 1-pentyl-l, 2, 3, 4-tetrahydro-2-carboline carboxylic acid-(3)].

Data were presented of the formation of the above indole derivative and of the resulting consumption of l-tryptophan and n-hexanal.

The possible ocurrence of the formation of Harmala alkaloids, i.e. 2-carboline derivatives, through in vitro digestion of soybean with acid proteinases was discussed.

A carbonyl-trapping ability of l-tryptophan was suggested.     

Changes of Linoleic,Arachidonic and Eicosapentaenoic Acids in Rat Platelet,Aorta and Plasma Lipids after Changing from a Sardine Oil Diet to a Corn Oil Diet

When rats were fed on a diet containing sardine oil (SO) for 10 days, 20:5 (eicosapentaenoic acid) was incorporated into the platelet, aorta and plasma lipids. The 20:5/20:4 (arachidonic acid) ratios of phospholipids were higher in platelets than in aortas. When the diet was changed from SO to corn oil (CO), the levels of 20:5 in the plasma lipids and platelet phospholipids decreased with an increase of 20:4. Although the 20:5 levels of phospholipids in the aortas decreased, 20:4 did not increase during feeding with the CO diet for 4 days. The 20:5/20:4 ratios of the phosphatidylcholine in platelets and aortas rapidly changed from 5.0 and 1.1 to 2.4 and 0.6, respectively. The linoleic acid level of phosphatidylcholine in platelets and aortas increased rapidly by changing from the SO diet to the CO diet, but this fatty acid was not incorporated into phosphatidylinositol of the platelets and aortas.     

Studies on the Metabolic Products of Macrosporium porri Elliott

Macrosporin C₁₆H₁₂O₅, a metabolic product of Macrosporium porri Elliott, has been proved to be mono-methyl-mono-methoxy-di-hydroxy-anthraquinone, owing to the fact that macrosporin monomethylether was oxidized with CrO₃ to 5-methyl 4-methoxy phthalic acid.     

Biological Activities of Fundamental,Carbohydrate Skeleton of Lipid A Containing Amide-linked 3-Hydroxytetradecanoic Acid

In the initial stage of hydrolysis, exo-ß-(l-→3)-d-glucanase from Basidiomycetes sp. QM 806 cleaved laminaran from Eisenia bicyclis with a pattern resembling an endo-hydrolase. Five kinds of intermediate gluco-oligosaccharides were separated by a combination of gel filtration and HPLC. They were shown to be 3²-O-ß-d-glucosyl-gentiobiose, 3²-O-ß-d-gentiobiosyl-gentiobiose, 3³O-ß-d-glucosyl-gentiotriose, 3⁴-ß-d-glucosyl-3²-O-gentiobiosyl-gentiobiose, and 3³-O-ß-d-gentio-biosylgentiotriose by enzymic hydrolysis and methylation analysis as well as by ¹³C NMR spectroscopy. As a result, such kinds of ß-(l → 3)-ß-(l→6)-linked oligosaccharides could be accounted for in the initial cleavage, and they were hydrolyzed ultimately to glucose, gentiobiose, and gentio-triose. It suggests that a single (1 → 3)-linkage on a block of (1 → 6)-links show some resistance to attack by this enzyme.     

Application of Plasmid to ATP Production by E. coli

A variety of immunomodulators were synthesized by combining biologically active derivatives of 1-thio-muramoyl dipeptide with 4-O-phosphono-d-glucosamine derivatives related to bacterial lipid A, and using the (succinoylamino)undecanoyl group as a spacer. Their immunoadjuvant activities in guinea-pigs were examined.     

Micro-analysis of Amino Acids with Fluorescein-isothiocyanate

The separation and identification of fluorescein-thiocarbarnyl (FTC-) amino acid II were accomplished by one- and two-dimensional thin-layer chromatography. The authentic samples for identification of amino acids were synthesized with fluorescein-isothiocyanate II (FITC II) and 21 amino acids. These FTC-amino acids were studied spectrometrically.

For quantitative estimation of FTC-amino acids, the fluoroscopy was used. It was found that the fluorescence intensity was proportional to the concentration of FTC-amino acids in 2 pmole/ml to 20 nmole/ml range. Recovery of FTC-derivatives on silica gel plate was about 80%.     

Comparative Study between Gas Chromatography and Ion-exchange Chromatography on Amino Acid Analysis of Foods

Lactobacillus brevis and Saccharomyces cerevisiae were completely sterilized by the supercritical (SC) CO2 micro-bubble method. Gaseous (G) and liquid (LQ) CO2 were used in a similar manner to compare the sterilizing effect. Among the three treatments, the microorganisms were only effectively sterilized by the SC CO2 treatment at 25 MPa and 35°C.     

Bitter Taste of H-Pro-Phe-Pro-Gly-Pro-Ile-Pro-OH Corresponding to the Partial Sequence (Positions 61 ~ 67) of Bovine β-Casein,and Related Peptides

The bitter components of cheese are hydrophobic peptides which are produced during the process of enzymatic digestion, and some of the isolated bitter peptides are derived from the middle portion of β-casein. However, quantitative examination of the bitter taste is seldom performed. We synthesized two hydrophobic peptides, H-Pro⁶¹-Phe-Pro-Gly-Pro-Ile-Pro⁶⁷-OH and H-Tyr⁶⁰-Pro-Phe-Pro-Gly-Pro-Ile⁶⁶-OH, which correspond to common portions among the isolated bitter peptides, in order to determine how bitter they were. From the results of sensory analysis, it was found that the synthetic peptides exhibited a bitter taste with threshold values 0.25 and 0.16mm, respectively. We also synthesized their fragments and analogs, and discussed the structure-bitterness relationship.