Rikagaku Kenkyusho

Tadahiko Ando

Takehiko Shibata

Shukuko Ikawa

Koki Horikoshi

Eiji Hayase

Yoshifumi Oikawa

Hiroomi Watabe

Norio Kamiyama

Koichi Yoshida

Tokuji Kitsunai

Cholung Kim

A novel Endo-deoxyribonuclease A (Endo-DNase A) which has the substrate specificity of recognizing specific base sequence in double-stranded deoxyribonucleic acid (DNA) molecules and cleaving the strands at specified sites in the DNA to produce specific DNA fragments and, a process for the production of the Endo-DNase A by culturing a microorganism belonging to the genus Saccharomyces or Pichia.

Endo-deoxyribonuclease and process for the production thereof

Disclosed is a process for the preparation of deoxyribonucleases (DNases) which comprise culturing a novel transformant belonging to the genus Bacillus, collecting a cell-free extract from cells obtained during a period ranging from the late logarithmic growth phase to the initial stage of the stationary growth phase, and subjecting said cell-free extract to fractionation or separation to obtain two or more DNases each of which possessing different substrate specificity.

Process for preparation of deoxyribonucleases

The present invention relates to novel enzymes which decompose nucleic acid and are endowed with a substrate specificity recognizing specific biological deoxyribonucleic acid and cleaving specific bonds thereof to produce fragments of deoxyribonucleic acid of specific sizes and which are obtained by culturing microorganisms belonging to genus Bacillus and purifying the cell free extract thereof by such treatment as streptomycin treatment, ammonium sulfate precipitation, ion exchange chromatography, gel filtration or combination of these processes.

Novel endonuclease and process for production thereof

The present invention relates to new enzymes which decompose nucleic acid and are endowed with a substrate specificity recognizing specific biological desoxyribonucleic acid and cleaving specific bonds thereof to produce fragments of desoxyribonucleic acid of specific sizes and which are obtained by culturing microorganisms belonging to genus Bucillus and purifying the cell free extract thereof by such treatment as streptomycin treatment, ammonium sulfate precipitation, ion exchange chromatography, gel filtration or combination of these processes.

The present invention relates to a throw-in type colorimeter having a defoaming mechanism comprising a double-cylinder whereby it is possible to very easily detect the optical density of the solution to be examined, and more particularly to a thrown-in type colorimeter equipped with a defoaming device in which a downward flow is created in a cylinder by means of the liquid level column difference in the inlet of the cylinder to let the bubbles in the solution escape upwardly therefrom and also equipped with an upward solution flow passage to provide a communicating passage between the outer and inner cylinders to form a down flow in the outer cylinder and drive the remaining bubbles out of the solution in the outer cylinder by the twice reversed flow while removing the bubbles residing in the measuring chamber by the agitated solution flow.

Throw-in type colorimeter

A new deoxyribonuclease (DNase) having preservability and high temperature stability is provided by cultivating a new strain M-26 of the genus Bacillus in an alkaline culture medium. The DNase has such a specificity that it very selectively cleaves phosphodiester bonds between deoxyguanosine and deoxyguanosine in a molecule of deoxyribonucleic acid (DNA) while leaving phosphate groups at the 5'-position.

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Tokyo, Japan

Tadahiko Ando