Studies on the Glucanase of Sclerotinia Libertiana

Preparations of glucan obtained from baker’s yeast and sclerotia of Sclerotinia Libertiana were found to be completely hydrolysed by enzymes of the Sclerotinia fungus. Some differences in the molecular structure of the glucans were found upon examination of the modes of degradation by the successive action of Rhizopus- and Sclerotinia enzyme preparations of which the former had only a partial hydrolytic effect.

The dissolution of glucan in intact cells of yeast, that could be estimated from the rate of autolysis of the cells, was proved to be insignificant on the action of glucanase alone in the Sclerotinia enzyme solution. The combined action of glucanase with lipolytic enzyme in the fungus enzyme solution are shown to promote the solubilization of intact yeasts and sclerotium cells.     

Studies on the Glucanase of Sclerotinia Libertiana

Glucanase-treatment of yeast cells was shown to increase the glucose fermenting activity, and decrease the sucrose and maltose fermenting activity. Also, lipase–and phospholipase–treatment decreased the fermenting activity on these sugars. However, the effects on the disaccharide fermenting activity could be reversed under various growth conditions of the yeast cells.

From these results, structural factors envolved in the transport of fermentable sugars into yeast cells are discussed.     

Biochemical Studies on Rice Bran Lipase

Lipase extracted from defatted rice bran with calcium chloride solution was purified by ammonium sulfate precipitation, followed by successive column chromatographies on DEAE-cellulose, Sephadex G-75, CM-Sephadex C-50 in the presence of calcium ion. The specific activity of the purified enzyme was 4.7 units/mg protein and 480 times that of starting crude extract. The homogeneity of the enzyme protein was criticized by polyacrylamide gel disc electrophoresis and ultracentrifugation. The enzyme protein also behaved homogeneously in ampholine electrophoresis, indicating the isoelectric point of 8.56. The sedimentation coefficient of the enzyme was determined to be 2.97 S, and the molecular weight to be 40,000 by Archibald’s method. According to the measurement of optical rotatory dispersion of the enzyme, ORD constant, λ_c, Moffitt-Yang parameters, a₀ and b₀, were evaluated to be 239 mμ, ?164 and ?123, respectively.     

Biochemical Studies on Rice Bran Lipase

Some chemical properties of the rice bran lipase were studied. The enzyme protein contained 14.98% nitrogen and consisted of 312 amino acid residues. It also contained a certain amount of lipid. The amino-terminal amino acids of the enzyme protein were shown to be glutamic acid and the carboxyl-terminal amino acids to be glycine and serine. The treatment of the enzyme protein with 8 m urea containing 1×10^?3m EDTA (ethyl-enediaminetetraacetic acid) seemed to cause dissociation of the subunits of the enzyme protein. From this observation and the results of the terminal amino acids analysis, it was presumed that the enzyme protein was composed of at least two types of subunits.     

Biochemical Studies on “Bakanae” Fungus. Part 54

Phosphate compounds in potato tubers were fractionated by ion-exchange chromatography. By the use of radio-phosphorus, the following compounds were tentatively identified to be present in potato tubers: G-1-P, G-6-P, F-6-P, FDP, PGA, AMP, UMP, ADP, UDPX, UDPG and ATP. When the tubers were stored at a low temperature, the contents of organic phosphate compounds showed a considerable increase over those of potatoes stored at a high temperature. However, the relative composition of each component was not much influenced by the storage temperature except ATP which showed a great increase at a lower temperature.     

Biochemical Studies on Vitamin B12 Part XI

In Part X, the authors published studies on vitamin B₁₂-like activity of cobalt-porphyrin-derivative prepared from radish-leaves, and the physiological significance of the compound as an active component in the intermediary metabolism of vitamin B₁₂ was described. , Afterward, pure chlorophyll a and b were isolated by column chromatography and the vitamin B₁₂-like activities of Co-porphyrin a and b were repeatedly confirmed.

Recently, effect of Co-porphyrin on the biosynthesis of real vitamin B₁₂ has been tested and the confirmation was also successfully completed by bioautography and paper electrophoresis.

In the present communication, it is discussed as of special importance that cobalt-porphyrin may be the active principle for the formation in vivo of vitamin B₁₂.     

Biochemical Studies on the Formation of the Silkprotein

The progression of fibroin in the inside of the silkgland during growth of the fifth instar was elucidated by tracing radioactive fibroin which was made of C¹⁴ glycine. Each fibroin synthesized by the posterior division at different period of the fifth instar moves, in an ordered fashion, in the inside of the gland along the middle and anterior division during growth of the silkworm. Furthermore, fibroin present in the middle division of the silkworm just before spinning is due to the successive disposition, in the order synthesized, of each portion of fibroin synthesized at different periods of the fifth stage.     

Biochemical Studies on the Formation of the Silkprotein

A large part, about 70 per cent, of the silkproteins produced by one silkworm is directly derived from the proteins of the mulberry leaves (direct formation), but some part of the silk-proteins, about 30 per cent, is also derived from the tissue proteins and body fluid proteins, in relation to the metamorphosis of the silkworm larva (indirect formation); there are two pathways in the formation of the silkproteins during the growth of the silkworm larva, i.e., direct formation and indirect formation.     

Biochemical Studies on “Bakanae” Fungus. Part 48–50

The outline of this report has already been published in this Journal appearing under “Communication to the Editors” A new gibberellin which was named gibberellin A₄ was isolated and characterized.     

Biochemical Studies on “Bakanae” Fungus. Part 56–57

To confirm the location of the lactone ring at ring A of gihberellin A₃, selenium de-hydrogenation experiments were conducted in various ways. The results thus obtained and NMR spectrum studies rather support structure (III).     

Biochemical Studies on “Bakanae” Fungus. Part 51–53

The outline of this report has already been published in this Journal as a communication to the Editors. The relation among four isomers, gibberellin A₁, gibberellin C, pseudogibberellin A₁ and isogibberellin A₁ was clarified. The partial structure of gibberellin C is presented.     

Biochemical Studies on Bakanae Fungus. Part 64. The Physiological Action of Gibberellin

The activities of various enzymes were examined in the first and second leaves of rice seedlings treated with gibberellin A. GIB treatment resulted in more or less decrease in the activities of malic dehydrogenase, alcohol dehydrogenase, pyruvic carboxylase, glutamic-aspartic transaminase, glutamic decarboxylase, glycolic acid oxidase and cytochrome oxidase on the basis of the enzyme solution. Increase in peroxidase activity was remarkable by GIB treatment when guaiacol and pyrogallol were used as hydrogen donor, but increase was not so much by use of p-phenylenediamine and p-methylaminophenol sulfate.     

大麦脂肪酶的研究进展

脂肪酶以其独特的优势在各个领域都有其潜在的应用前景。在高等植物中,种子萌发过程中脂肪酶活性较高,其活性与食品的加工方法有关。应用不同的方法测定大麦脂肪酶酶活力,得到的结果也不同。详细介绍了大麦脂肪酶的部分酶学性质。