Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1998-12-22
2001-11-06
Pezzuto, Helen L. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C525S285000, C525S327400, C526S271000, C526S272000, C526S317100, C526S333000
Reexamination Certificate
active
06313201
ABSTRACT:
This invention relates to a modified catalase which is modified with specific copolymer and is highly stable, a composition containing said modified catalase and a process for preparing the catalase.
Proteins are in general stable in vivo. However, proteins which are once isolated from living bodies and purified are so unstable that they are denatured when heated or brought into contact with acids, alkalis or organic solvents, until proteinaceous functions of their own are lost. This is due to destruction of the specific higher-order structure of protein.
Catalase is a known enzyme which catalyzes decomposition of hydrogen peroxide. As catalase is one of proteins, there is no exception.
Consequently, studies have been made for applying modified enzymes which are prepared by chemical modification of proteins with synthetic polymers and are stabilized against heat or acids, alkalis or organic solvents to fields of medical, pharmacological, engineering or agricultural sciences.
Functions to be expected to the modified proteins are: (1) disappearance of antigenicities which may cause problems when the proteins are administered as a pharmaceutical in vivo, and extension of internal retention time; (2) a missile therapy using medicines such as antibiotics or antitumor agents bound with antibodies; and (3) catalysts for bioreactors which are made soluble in organic solvents by being modified with amphipatic synthetic polymers.
As modifiers used for stabilization of enzymes, a modification of catalase, for example, with 2,4-bis(o-methoxy polyethylene glycol)-6-chloro-s-triazine is reported (Biochem. Biophys. Res. Commun. Vol. 125, No. 2, 761-766, 1984). This is, however, for the purpose of having catalase solubilized in organic solvents, and it is hard to produce a large amount of modified enzymes, because the method requires several steps.
Further examples of the other stabilized modified enzymes are a modified protease (JP 6-205675A) and a modified asparaginase (JP 5-336966A).
Catalase in itself, however, is denatured in the presence of peroxoacid salts such as sodium peroxocarbonate and sodium peroxoborate. Consequently, no catalytic action of catalase can be expected in the presence of peroxoacid salts.
The first aspect of the present invention is to provide modified catalase which can be stored with highly stability (hereinafter sometimes designates simply as stored stability) without disturbance of original properties of catalase for a long term in the presence of peroxoacid salts such as sodium peroxocarbonate and sodium peroxoborate, and can be mass-produced by simple operations.
The second aspect of the present invention is to provide a composition containing the modified catalase.
The third aspect of the present invention is to provide a process for preparing the modified catalase.
We have found that catalase which is modified by copolymers having at least both a polyoxyalkylene group and an acid anhydride group in the same molecule maintains stability for a long term without losing stability even in the presence of peroxoacid salts such as sodium peroxocarbonate and sodium peroxoborate.
REFERENCES:
patent: 5081111 (1992-01-01), Akimoto et al.
patent: 05336966 (1993-12-01), None
patent: 06046847 (1994-02-01), None
patent: 06141857 (1994-05-01), None
patent: 07222586 (1995-08-01), None
Nanba Satoshi
Ohhashi Syunsuke
Suzuki Tomomi
Yasukohchi Tohru
Mitsubishi Gas Chemical Company Inc.
Pezzuto Helen L.
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