Tsutomu Yamaguchi

Studies on dextranase. II. New exo-dextranase from Brevibacterium fuscum var. dextranlyticum.

Abstract Dextranase (EC 3.2.1.11) from Brevibacterium fuscum var. dextranlyticum was purified by ammonium sulfate fractionation, gel filtration of Bio Gel P-30 and DEAE-cellulose column chromatography. This preparation gave a single protein band with disc electrophoretic analysis. The dextranase was most active over a pH range from 7.0–7.5 in a 30 min reaction and was stable over a wide pH range from 5.0–11.0 at 37 °C for 12 h. The enzyme was activated approximately 2 fold by cysteine and EDTA, and inactivated by iodine, HgCl2, N- bromosuccinimide and CuSO4. In the dextranase hydrolysis reaction, isomaltotriose was the only digestion product with reducing power from dextran and reduced isomaltodextrins. Enzymatic hydrolysis also lowered the specific viscosity of the reaction mixture slowly. These results suggest that the enzyme is the new exo-type dextranase.

Properties of protoplast-bursting factor, a substance isolated from pig pancreas.

Abstract 1. 1.|A purified preparation of protoplast-bursting factor was shown to be homogeneous by electrophoresis and ultracentrifugation. 2. 2.|From sedimentation equilibrium and gel filtration experiments a value of 13 000 was obtained for the molecular weight of protoplast-bursting factor. 3. 3.|The substance was denatured by the addition of 7 M urea and 50 mM DFP. On the other hand, the activity was promoted by Mg 2+ or Ca 2+ . 4. 4.|It did not decrease the surface tension of saline even in high concentrations. 5. 5.|Protoplast-bursting factor lysed the protoplasts of Gram-positive bacteria, but not the spheroplasts of Gram-negative bacteria.

Detection of Phospholipase C and Hemolysin in the Cultures of Several Streptoverticillium

Phospholipase C [EC 3.1.4.3] has been detected in the cultures of such bacteria as•@Clostridium (4), Bacillus (1), Pseudomonas (3) and Staphylococcus aureus (2). Hemolytic activity of Streptomyces has been used for a long time as one of the criteria for the identification and characterization of Streptomyces. In the previous paper (5), we reported that the culture filtrate of Streptoverticillium hachijoense has phospholipase C activity. This paper describes the presence of phospholipase C in several other strains of the same family. The correlation between phospholipase C and hemolytic activity will be discussed. Cultivation of the test strains was performed as described in the first paper of this series (8). Strains used were : Sty. albireticuli IFO 12737, Sty. cinnamoneum IFO 12852, Sty. flavopersicum IFO 12769, Sty. griseocarneum IFO 12776, Sty. hiroshimense IFO 12785, Sty. mashuense IFO 12888, Sty. mediocidicus IFO 13202, Sty. hachijoense A-1143. Phospholipase C and hemolytic activities were determined according to the methods described in preceding paper (5). Isoelectric focusing was carried out as reported by Vesterberg and Svensson (7). After removal of insoluble material by centrifugation, the clear culture supernatants were dialyzed for 24 hr against distilled water at 4 C. The dialyzed solutions

Isolation of protoplast-bursting factor from pig pancreas

Abstract 1. 1. During studies on the structure of the protoplast membrane, the effects of various enzymes on the protoplast of Bacillus megaterium have been investigated. 2. 2. A substance contained in lipase from pig pancreas had strong bursting activity on the protoplasts. 3. 3. This substance was isolated from pig pancreas by column chromatography on Amberlite IRC-50, and crystallized from acetone-water. 4. 4. The substance was extremely stable to heat. The mol. wt. was about 10 000, and the molecule was constituted from amino acids. The substance was not identified with any of the known enzymes used in these experiments. 5. 5. The substance has been named protoplast-bursting factor.

Action of Protoplast-bursting Factor upon Microorganism: Part I. The Effects on the Permeability Barrier

Protoplast-bursting factor (P. B. factor) has a little antibacterial activity and is capable of inhibiting the growth of Bacillus megaterium.The cell suspensions required P. B. factor and Mg++ for the oxidation of glucose-6- phosphate but did not require them for that of glucose.Leakage of various cellular components into the surrounding menstruum occured when the cell suspension was subjected to treatment with P. B. factor. These materials were identified as protein, deoxyribonucleic acid, ribonucleic acid, and amino acids.Under an electron microscope, the cytoplasm of the cells treated with P. B. factor was apparently less dense than the control, which seemed to suggest that the cytoplasm had leaked out of the inside of the cell through the membrane by the treatment of P. B. factor.