For the screening of potent proteases of plant origin, gelatinolytic activities were measured for various vegetables and fruits. Green asparagus, kiwi fruit and miut were found to possess high proteolytic activities. Optimum temperatures for the activities of green asparagus and miut were 40 to 45°C and that of kiwi fruit was 60°C. Optimum pHs for the three activities were in neutral or slightly alkaline regions. The proteolytic enzymes of kiwi fruit and miut were stimulated by cysteine and EDTA but that of green asparagus was unaffected by them.

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A dextransucrase inhibitor, ribocitrin, was purified about 580-fold from a culture broth of Streptomyces neyagawaensis MF980-CF1 by combination chromatography.
Ribocitrin is a previously unknown type of oligosaccharide composed of ribose. It inhibited the crude preparation of dextransucrase noncompetitively with regard to sucrose and the inhibitory activity (Inh%) was sensitive to pH. It was very stable at alkaline pH values, but gradually lost its inhibitory activity as the acidity increased. It had no antimicrobial activity. It did not inhibit glycoside hydrolases and was not susceptible to the above enzymes. It had a low toxicity.
Plaque formation of Streptococcus mutans E49 on a smooth glass surface was diminished by ribocitrin and the colony form of this microorganism on Mitis Salivarius agar was evidently affected by ribocitrin.

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Experiments were carried out to elucidate the correlation between gel chromatographic profiles and rheological properties of dope with respect to the spinnability of soy protein. It was found that dope prepared with 20% protein concentrate and 1.2% sodium hydroxide showed a good transition zone from rubber-like elasticity to rubber-like flow, as frequency (log ω) in limitation was increased from - 1 to 1, and also the dope showed good spinnability when prepared in the above manner. Good spinnable dopes showed three main fractions in the gel chromatographic profiles on using a Sepharose 4B gel column. The first peak was of a high molecular weight fraction (M_w>1, 000, 000) eluted at the void volume, the second peak was of low molecular weight fraction (M_w<200, 000; the peak was around 10, 000) eluted at the end of the gel chromatogram, and the third part was a gentle upward slope between the two peaks (1, 000, 000>M_w>200, 000). It was clear that the spinnabilities and rheological properties of dope depended on differences in composition of the three main fractions mentioned.

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Riboflavin(RF)-productivity of reseoflavin(RoF)-resistant strains of Staphylococcus aureus, Bacillus pumilus and Bacillus subtilis was studied. Two of three types of resistant strains of S. aureus were shown to produce more RF than the parent strains. Resistant strains of B. pumilus were also RF-producing, and one type (fp) of the resistant strains from B. subtilis HW produced a large amount of RF in the culture medium. The hereditary stability of RF-producing properties of the fp type was also shown.

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The major component of a purified sample of secretory IgA (SIgA) in colostrum was revealed as a single peak on gel filtration with Sepharose 6B, having an estimated molecular weight of 540, 000. The existence of a higher molecular weight component was suggested by a small shoulder on the ascending limb of the peak, but another component of IgA reported as IgA lacking the secretory component (SC) could not be found. When the purified SIgA was concentrated by dialysis against polyethylene glycol, its molecular size was apparently significantly decreased.
Analysis by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) showed that all SC in SIgA binds covalently. The band corresponding to the J chain was easily detected when a reduced and alkylated sample was analysed. Estimation of the molecular weight by SDS-PAGE gave the following values for each of the constituent polypeptide chains of bovine colostral SIgA: SC, 76, 000; H chain, 62, 000; L chain, 23, 000; and J chain, 18, 000. The molecular weight of the whole molecule was calculated to be 434, 000.
Analysis of carbohydrates by gas-liquid chromatography showed 6.8% neutral and amino hexoses, consisting of 0.4% fucose, 1.8% mannose, 1.1% galactose and 3.5% glucosamine. Galactosamine, which has been found in bovine free secretory component from milk, could not be detected.

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The inner structure of a lipid-containing phage, φNS11, was examined under an electron microscope. The thin-sectioned or urea-treated and negatively stained phage showed a central core and an outer shell. Treatment of the phage with chloroform or Tris-HCl (pH 8) visualized the outer and the inner protein shells, which had hexagonal outlines. Particles having tail-like structures were sometimes observed in 4M urea-treated samples. Based on these observations, a possible inner structure of the phage was proposed.

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Amylase inhibitors (amylostatins) other than those reported as S-AI were found in the culture filtrate of Streptomyces diastaticus subsp. amylostaticus No. 2476. They were separated grossly into F-1a, F-1b and F-2 fractions by column chrpmatography on Dowex 50W×4 (NH₄⁺) and by preparative high performance liquid chromatography. Each fraction was further separated by preparative paper partition chromatography (PPC). Fractions obtained by PPC had different inhibitory activities against various amylases. On the other hand, acid hydrolysis of each active inhibitory fraction produced amylostatin X' (C₁₃H₂₁NO₇) and/or amylostatin XG (C₁₉H₃₃NO₁₃). The diversities and common features of these amylostatins are discussed.

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For the purposes of decoloring raw sewage and use as an analytical tool in clinical fields, we tried to obtain microorganisms producing an enzyme which is reactive to bilirubin. One strain of microorganism (MT-1) showed strong ability to produce the enzyme.
The morphological and physiological characteristics of strain MT-1 were studied. This strain was found to belong to Myrothecium verrucaria.
For the production of the enzyme, this strain was aerobically cultured at 25°C in a jar fermentor which contained potato-glucose medium. The highest activity was obtained after 62-hr cultivation.
This enzyme was also produced by other strains belonging to Myrothecium.

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Lutein, one of the most common carotenoids, has been believed to be optically inactive in the visible region. Lutein was found, however, to acquire a very strong circular dichroic (CD) activity in this region when dispersed in an aqueous solution in the presence of sodium dodecyl sulfate (SDS). The CD spectrum of lutein had positive and negative extrema before and behind a crossover at about 390 nm, respectively. The signs of the extrema were inverted when the amount of SDS was increased. Further addition of SDS destroyed the CD activity. These phenomena are suggested to reflect a sequence of events, namely; 1) the formation of a helical assembly of the lutein molecules; 2) a wholesale structural change of the assembly resulting in the inversion of its chirality, and 3) the breakdown of the assembly followed by the inclusion of the lutein molecules into SDS micelles.

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Envelope fraction I prepared from a φX174 sensitive host, KD4301, showed a strong eclipsing activity, while the lipopolysaccharide (LPS) fraction showed a weak activity. The eclipsing activity in envelope fraction I was sensitive to heat treatment, while that in the LPS fraction was insensitive. When the complete phage particles (114S) were treated with envelope fraction I, the eclipsed particles (70S) and a rapidly sedimenting component were obtained, but when they were treated with LPS, only 70S eclipsed particles were obtained. Electron microscopic observation showed that there were two types of eclipsed particles formed on treatment with fraction I; in one of them phage DNA was extruded from the phage particles as a thick bundle, and in the other more than 95% of the phage DNA was extruded from the phage particles. The rapidly sedimenting component was the membrane-eclipsed particle complex. LPS gave only one type of eclipsed particles in which DNA was extruded as a thick bundle. These results indicate that a heat labile component in the cell envelopes other than LPS is involved in the extrusion of φX174 DNA.

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The structure of acidic polysaccharide from strain No. 626 of Aeromonas hydrophila was studied. The possible structure shown was proposed from the results of methylation analysis, acetolysis, partial acid hydrolysis and Smith degradation.

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A new ftavoprotein enzyme, GSH oxidase, was found in the aqueous extract of a wheat bran culture of Penicillium sp. K-6-5. The oxidase is also produced extra and intracellularly in the liquid culture, although the production is much lower than that in the wheat bran culture.
The enzyme has been purified to homogeneity. It shows absorption maxima at 270, 350 and 444nm and a shoulder around 465nm and contains 2mol of FAD per mol of enzyme. The enzyme has a molecular weight of approximately 95, 000 and consists of two subunits identical in molecular weight (about 47, 000). Balance studies show that 2 mol of GSH are converted to 1 mol of GSSG and hydrogen peroxide with the consumption of 1 mol of oxygen. In addition to GSH, several sulfhydryl compounds are oxidized by the enzyme to a lesser extent. The Michaelis constants are as follows: 0.69mM for GSH, 3.6 mM for L-cysteine and 6.7 mm for dithiothreitol at pH 7.4. The oxidase scarcely acts on reduced RNase A in contrast to the known sulfhydryl oxidases. The isoelectric point and the optimal pH are 4.2 and 7.4, respectively. The enzyme activity is completely inhibited by addition of 1 mM ZnSO₄.

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The effects of enzymic or chemical fragmentations and of chemical modifications on the antigenic properties of bovine β-lactoglobulin were examined using specific mouse IgE antibody. The antigenic reactivity of β-lactoglobulin derivatives was represented in terms of their ability to neutralize specific IgE antibodies assayed by passive cutaneous anaphylaxis in rat. The tryptic, chymotryptic or peptic hydrolysate free of native β-lactoglobulin had no antigenic reactivity but the fragments obtained after CNBr cleavage retained the ability to bind the antibody. Modification of the sulfhydryl group, arginine or tryptophan residues and amino groups had no effect on antigenic reactivity but a little decrease in the reactivity was observed on the cleavage of the two disulfide bridges. These results suggest that one sulfhydryl group, two arginine and tryptophan residues and most of the amino groups are out of antigenic sites in β-lactoglobulin and that the antigenicity depends on the conformation maintained by the disulfide bridges.

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A strong Cotton effect associated with the ring oxygen was studied in aromatic glycofuranosides. Phenyl and phenyl 1-thioglycofuranosides gave a strong band at 180nm and 200-210nm respectively, similar to the corresponding glycopyranosides, suggesting that the ring oxygen helicity rule can be extended to these aromatic glycofuranosides or the band can be used to determine their anomeric configurations and conformations.

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In addition to HMG-CoA reductase, another HMG-CoA utilizing enzyme is present in the Mt fraction of sweet potato root tissue and its activity interferes with the assay to HMG-CoA reductase activity.

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Zymolyase B decreased the turbidity of a yeast cell wall suspension by about 50% and caused release of peptide-mannan from the cell walls. However cell walls treated with the enzyme still maintained the cell shape. The effect of the enzyme on the cell walls was inhibited by yeast mannan and completely counteracted by treatment of the enzyme with DFP. The activity was not affected by pH, but was considerably reduced by incubation of the enzyme at 55°C for 15 min, a treatment that did not affect the proteolytic activity. Heat-treatment decreased the molecular weight of the enzyme from 29, 000 to 22, 500 and its sensitivity to yeast mannan. Yeast mannan caused noncompetitive inhibition of the proteolytic activity of the native enzyme and competitive inhibition of that of the heat-treated enzyme. Modification of tryptophan residues of Zymolyase B resulted in decreased sensitivity to yeast mannan and a decrease in the activity of the enzyme on yeast cell walls as well as heat-treatment. On the basis of these results, it is hypothesized that Zymolyase B binds to the cell wall mannans and changes their conformation, making the attached proteins susceptible to proteolysis, and then releases peptide-mannan from the cell walls.

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Several metabolites responsible for the toxic manifestations of Valsa ceratosperma (Toda et Fries) Maire, a phytopathogenic fungus of the Japanese apple canker, have been isolated from its culture filtrate after growth on apple branch extract. Chemical and spectrometric studies revealed the products to be degradation products of phlorizin which is a dominant component distributed in leaves, stems, fruits and roots of apple. The toxic substances were identified as 3-(p-hydroxyphenyl) propionic acid, phloroglucinol, p-hydroxyacetophenone, p-hydroxybenzoic acid and protocatechuic acid. All of these compounds except p-hydroxyacetophenone were detected in the lesions of apple trees infected by V. ceratosperma. The fungus cultivated in a medium containing added phlorizin also produced the five toxic substances mentioned above. These results suggest that phlorizin is involved in the specific relationship between the host and the pathogen, indicating that the degradation products of phlorizin play important roles in the production of symptoms of infected apple trees.

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A bacterium which can utilize potato starch granules as sole carbon source was isolated and identified as Bacillus circulans from its physiological and biochemical properties. Scanning electron microscopic observation of potato starch granules recovered from the culture broth revealed that granules were degraded gradually from their surface resulting in elongated granules with layered structures on their surface. This bacterium produced extracellular amylase which can digest potato starch granules in vitro. The amylase has a unique property in that it produces only maltohexaose from gelatinized starch in the early stage of the reaction. For the production of this amylase potato starch was found to be most effective while soluble sugars including gelatinized starch and maltose had little effect.

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An extracellular acid phosphatase from Ustilago esculenta was purified to homogeneity on the basis of polyacrylamide gel electrophoresis. It was a glycoprotein with an isoelectric point of 4.7. The molecular weight of the enzyme was estimated to be about 343, 000 by gel filtration on Sephadex G-200, whereas on SDS-polyacrylamide gel electrophoresis, the enzyme gave a single protein band with a molecular weight of 116, 000. This result suggests that the enzyme consists of three identical subunits. The enzyme showed an optimum activity at pH 4.5, retained 90% of its activity for 10 min at 55°C and had a Km value of 0.25 mM for p-nitrophenylphosphate. No definite substrate specificity of the enzyme was observed.

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To establish an intact cell system to determine the rate of vitamin B6 (B6) biosynthesis, conditions suitable for the reaction were examined. Cells of Escherichia coli B WG2, a pdxH. mutant, were used for the reaction. Pyridoxal-starved cells of a stationary phase culture showed a negligible change of cell mass and a constant increase of B6 in the reaction. The rate of B6 biosynthesis was reliably determined with a 2-hr reaction initiated with cells of 0.10 to 0.15mg per ml. The influence of endogenous metabolites was completely abolished by the use of such a low concentration of the starved cells.
When glucose was used as a sole carbon substrate in the reaction system, the maximum rate of B6 biosynthesis was determined to be 0.5 to 0.6 nmol per mg cells per hr. The maximum rate increased to 0.8 to 0.9 nmol per mg cells per hr on supplementation of glycolaldehyde to the reaction mixture. The result led to the conclusion that the rate-limiting step in the reaction sequence of B6 biosynthesis lies the process of incorporation of the 5-5' carbon fragment of the B6 molecule. This was also confirmed by a growth experiment with the wild type strain.

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