A soluble arylamidase from the hog small intestinal mucosa was purified by ammonium sulfate fractional precipitation, Sephadex G-200 gel filtration, column chromatography on DEAE-cellulose and a second Sephadex G-200 gel filtration, The final preparation was homogeneous in polyacrylamide gel disc electrophoresis at pH 8.3 and was purified approximately 140-fold.
The molecular weight of this enzyme was estimated to be approximately 13×10⁴. The maximum activity was observed at a concentration of 1×10^-3 M cysteine or reduced glutathione and was accelerated about 1.5-fold by the addition of 1×10^-4 M Co²⁺. This enzyme strongly hydrolyzed L-lysyl-p-nitroanilide, L-leucyl-β-naphthylamide and L-leucyl-p-nitroanilide, but weakly hydrolyzed L-leucylglycylglycine and L-leucylglycine.

View full abstract

Biodegradation by soil microorganisms of fluorescent whitening agents (FWAs), disodium 4, 4'-bis (2-sulfo-styryl) biphenyl (FWA-1) and disodium 4, 4'-bis[(4-toluidino-6-morpholino-1, 3, 5-tria-zine 2-yl) amino] stilbene-2, 2-disulfonate (FWA-2) was investigated.
Each FWA was perfused in soil separately in dark condition. During the first 2 weeks of soil perfusion optical density at 348 nm (λ_max, of both agents) and TOC values of the perfusion solution parallel decreased due to FWA adsorption into soil particles. The perfusion soil was oversaturated with the FWA agents which were added repeatedly during next 8 weeks.
After 10 weeks of perfusion the optical densities of the perfusion solution decreased rapidly with no change in TOC values upon addition of 10 ppm of FWAs.
The UV spectra of FWA-1 and FWA-2 solutions after soil perfusion and UV exposure were respectively closely similar to each other. The UV spectrum of FWA-2 solution after soil perfusion was closely similar to that of the cis-isomer of the agent.
The results suggested that the FWAs were partially degraded to organic intermediates by soil microorganisms.

View full abstract

The decomposition of detergent whitening agents, bis-styryl biphenyl type (FWA-1) and triazinyl type (FWA-2), was investigated. After exposure to UV light and soil perfusion in darken condition, the agents were examined by reverse phase high performance liquid chromatography (HPLC). Several fluorescent components were detected in FWA samples exposed to UV light. Since the TOC values of these samples did not decrease during treatment, the FWAs were assumed to be partially degraded to several organic intermediates. Comparisons of HPLC chromatograms showed that FWA samples exposed to UV light and those subjected to soil perfusion both shared several peaks at the same retention times. One of the common peaks was assumed to be a cis-isomer of FWA-2 from UV spectra. The results demonstrated the biodegradation of FWAs by soil microorganisms, and the usefulness of HPLC in analyses of FWA biodegradation by soil microorganisms.

View full abstract

Investigations were conducted on the carbohydrate constituents of mycelia of highly proteolytic mutants and hybrids by protoplast fusion of strains belonging to Aspergillus oryzae.
Glucosamine content in both mycelia and the cell wall increased with increasing proteolytic activity during successive mutations with ultraviolet irradiation. In successive mutations, the amount of glucosamine in the cell wall reached 7_??_8g per 100g of mycelia. The glucosamine content was intermediate in hybrids, whose proteolytic activity was intermediate between both parents. A higher protease productivity seemed to accompany higher glucosamine content in hybrids. The ratio of glucose to mannose in the cell wall also increased with increasing protease productivity during successive mutations and hybridization.
Both the glucosamine content and the ratio of glucose to mannose in the cell wall may give useful indications of biochemical state of the mold during mutation and hybridization.

View full abstract

A homologous series (n=2_??_15 and 18) of bifunctional lysine derivatives linked with dicarboxylic acid was synthesized and tested for phage-inactivating activity, using a wide variety of phages, to examine the influence of elongation of the methylene chain [-(CH₂)_n-] between two ε-amino functional groups on inactivating activity. The results indicated the longer the methylene chain, the greater the inactivating activity. For n=2_??_9, the activity showed a zigzag pattern, being greater in odd-numbered n than at the next even-numbered n. For n=10_??_18, such a zigzag pattern of activity was not observed, except in n=12_??_15 for phage δA. In the case of phage MS 2, the activity pattern was different from that of other phages. These data suggest that the longer methylene chain, along with the ε-amino group, plays an important role in phage-inactivating activity. The zigzag pattern of activity observed in the shorter chain might be due to the optimum orientation of the two ε-amino groups in interaction with target sites in the phages.

View full abstract

LiOH at more than 20mM strongly inhibited the growth of Lactobacillus casei IFO-3831. The effect was remarkable at the initial log phase but weak at the end. In plate culture, 50mM LiCl strongly inhibited growth, whereas 50mM KCl, NaCl, RbCl, CsCl, NH₄Cl or CaCl₂ affected cell growth slightly. LiOH up to 16mM proportionately promoted the uptake of lithium ion, whereas at a higher concen-tration the uptake was increased. It was also found that LiOH at above 16mM induced the release of cellular N-acetylglucosamine and UV-absorbing substances. Thus it was suggested that the growth inhibition was due to a partial disarrangement of the cell membrane and wall.

View full abstract

The substrate specificities of aminopeptidase from Aspergillus oryzae (AOP), aminopeptidase I and II from Bacillus subtilis (BSP-I, BSP-II) and leucine aminopeptidase from swine kidney (LAP) were investigated with various synthetic peptides.
AOP rapidly hydrolyzed tripeptides, such as Leu-Gly-Gly, Leu-Ala-Gly and Leu-Gln-Gly, and mod-erately hydrolyzed Gly-Gly-Val, Leu-Gly-Gly-NH₂, Ala-Leu-Gly and Ala-Gly-Leu. The enzyme slowly hdrolyzed Pro-Gln-Gly, Pro-Leu-Gly and Leu-Lys-Lys, but scarcely hydrolyzed Leu-Gly and Leu-NH₂.
BSP-I rapidly hydrolyzed Leu-Ala-Gly, Pro-Gln-Gly, Ala-Leu-Gly and Leu-Gln-Gly, and moderately hydrolyzed Leu-Gly-Gly and Ala-Gly-Leu, but scarcely hydrolyzed Leu-Gly and Leu-NH₂. BSP-II rapidly hydrolyzed Ala-Leu-Gly, Leu-Gly-Gly and Leu-Ala-Gly, and moderately hydrolyzed Gly-Gly-Val, Leu-Gln-Gly, Ala-Gly-Leu and Pro-Gln-Gly, but hardly hydrolyzed Leu-Gly and Leu-NH₂. BSP-I preferentially hydrolyzed Pro-Gln-Gly and Leu-Gln-Gly rather than BSP-II, while BSP-II hydro-lyzed Ala-Leu-Gly, Ala-Gly-Leu, Gly-Gly-Val, Leu-Gly-Gly and Leu-Ala-Gly more rapidly than BSP-I.
LAP preferentially hydrolyzed various oligopep-tides that possessed L-Leu and L-Pro as the N-terminal amino acid, except Ala-Leu-Gly, and also hydrolyzed Leu-NH₂ and Leu-Gly-GIy-NH₂.

View full abstract

Changes in oxidation-reduction potentials (rH) of soy sauce mash (moromi) were investigated during lactic acid fermentation, in relation to the darkening phenomenon of the mash. A number of soy pediococci were examined for color-lightening ability in moromi-juice medium. The ability differe significantly among strains. Through brewing experiments, the color-lightening strains were shown to lower the rH of moromi and to maintairn it under 6.0 during the working period. However, the color-darkening strains did not significantly lower-the rH of moromi compared with the control, but kept it around 9.0 even during maxima growth. All strains were classified according toreducing activity, but did not differ much in other characteristics, such as sugar fermentation and decomposition of amino acids. In conclusion, the reducing activity of soy pediococci differed largely among strains, and the oxidation-reduction poten tials of fermented soy sauce mash were strongly affected by the strain employed.

View full abstract