Amylases

Details Amylases Amylases

1999-12-16

2002-06-11

Achutamurthy, Ponnathapu (Department: 1652)

Chemistry: molecular biology and microbiology

Enzyme , proenzyme; compositions thereof; process for...

Hydrolase

C435S183000, C435S200000, C435S201000, C435S069100

Reexamination Certificate

active

06403355

ABSTRACT:

TECHNICAL FIELD
The present invention relates to liquefying alkaline &agr;-amylases having high chelating-agent-resisting performance and are useful as a component for detergents.
BACKGROUND ART
&agr;-Amylases have been used widely in various industrial fields such as starch, brewing, fiber, pharmaceutical and food industries. Since they are known to be suited as one of the components of a detergent, they are incorporated even in an automatic dish washing detergent or a laundry detergent as a detergency reinforcing component (Enzymes in Detergency, p203, Marcel Dekker Inc., New York (1995)).
As liquefying &agr;-amylases useful for a detergent and having the optimum effects on the alkaline side, those previously found by the present inventors and derived from the strain Bacillus sp. KSM-1378 (FERM BP-3048) are known. Recently, &agr;-amylases having the optimum pH at around 8 to 9.5 are disclosed (WO95/2639). They resemble closely to those derived from the strain KSM-1378 in properties and structure.
In a detergent, a chelating agent such as phosphoric acid, citric acid or zeolite is incorporated to remove, from a washing liquid, cleansing-disturbing ions such as calcium ions. It has been known for long years that liquefying &agr;-amylases require calcium ions for expressing their enzyme activity but such calcium ions are deactivated by the above-described chelating agent or a stronger chelating agent EDTA [HANDBOOK OF AMYLASES AND RELATED ENZYMES, p43, The Amylase Research Society Japan(1988)]. In recent days, it is reported that X-ray crystallographic analysis of the liquefying &agr;-amylases known to date reveals that three calcium atoms exist in the molecule thereof and 13 amino acid residues are conserved with markedly high frequency [Structure, 6, 281(1998)].
Inhibition of enzyme activity by a chelating agent is also recognized in the above-described liquefying alkaline &agr;-amylase derived from the strain Bacillus sp. KSM-1378 (FERM BP-3048) and sufficient effects of this &agr;-amylase are not always exhibited when it is incorporated in an automatic dish washing detergent or laundry detergent. Liquefying &agr;-amylases (Termamyl and Duramyl, products of Novo Nordisk A/S) derived from
Bacillus licheniformis,
which are most frequently employed as a component of an automatic dish washing detergent or laundry detergent, are also insufficient in chelating-agent-resisting performance.
Among the liquefying amylases known to date, a liquefying &agr;-amylase (WO90/11352) derived from the strain belonging to Pyrococcus sp. and an &agr;-amylase (WO96/02633) which is derived from the strain belonging to Sulfolobus sp. and is effective in the liquefying step of a starch are free from the influence from a chelating agent. These enzymes however have the optimum acting pH in a range of 4 to 6 and 2.5 to 4.5, respectively and do not act in the alkaline range so that they are not suited as a component of a detergent.
An object of the present invention is therefore to provide a liquefying alkaline &agr;-amylase having higher chelating-agent-resisting performance than conventional amylases for a detergent and is useful as a component of a detergent; and a detergent composition having this liquefying alkaline &agr;-amylase incorporated therein.
Disclosure of the Invention
In one aspect of the present invention, there is thus provided a liquefying alkaline amylase having residual activity not less than 70% when treated at pH 10 and 45° C. for 30 minutes in the presence of 1 to 100 mM of EDTA or EGTA.
In another aspect of the present invention, there is also provided a DNA fragment encoding said liquefying alkaline amylase.
In a further aspect of the present invention, there is also provided a detergent composition containing said liquefying alkaline amylase.


REFERENCES:
patent: 9011352 (1990-10-01), None
patent: 9426881 (1994-11-01), None
patent: 9502639 (1995-01-01), None
patent: 9602633 (1996-02-01), None
Mischa Machius et al, Activation of Bacillus licheniformis a-amylase through a disorder order transition of the substrate-binding site mediated by a calcium-sodium-calcium metal triad, Jan. 12, 1998.
Edited by Jan H. van Ee et al, Enzymes in Detergency, copyright 1997 by Marcel Dekker, Inc.
Edited by The Amylase Research Society of Japan, Handbook of Amylases and Related Enzymes, copyright 1988 by Pergamon Press.

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