Chemistry: molecular biology and microbiology – Enzyme – proenzyme; compositions thereof; process for... – Stablizing an enzyme by forming a mixture – an adduct or a...
Reexamination Certificate
2000-06-20
2001-11-27
Prats, Francisco (Department: 1651)
Chemistry: molecular biology and microbiology
Enzyme , proenzyme; compositions thereof; process for...
Stablizing an enzyme by forming a mixture, an adduct or a...
C081S102000, C081S107000, C081S111000, C081S137000, C081S401000, C252S008910, C252S062200, C252S182280, C252S186380, C252S186390, C252S186430, C510S300000, C510S303000, C510S305000, C510S312000, C510S315000, C510S320000, C510S350000, C510S351000, C510S356000, C510S367000, C510S369000, C510S374000, C510S375000, C510S376000, C510S377000, C510S392000, C510S393000, C510S502000, C510S530000
Reexamination Certificate
active
06323014
ABSTRACT:
TECHNICAL FIELD
The present invention generally relates to the activation of redox enzymes by means of enhancing agents. More in particular, the invention is concerned with the activation of phenol oxidizing enzymes, especially in a process for bleaching stains on fabrics during washing.
BACKGROUND AND PRIOR ART
Redox enzymes are enzymes which catalyze the transfer of electrons from an electron donor to an electron acceptor. In the case of phenol oxidizing enzymes, the electron donor is usually a phenolic compound and the electron acceptor is molecular oxygen or hydrogen peroxide, which is thereby reduced to H
2
O. Phenol oxidizing enzymes are capable of using a wide variety of different phenolic compounds as electron donors, but they are very specific for molecular oxygen or hydrogen peroxide as the electron acceptor.
Examples of phenol oxidizing enzymes which use molecular oxygen as electron acceptor are laccases (EC 1.10.3.2), bilirubin oxidases (EC 1.3.3.5), mono phenol oxidizing enzymes (EC 1.14.18.1), catechol oxidases (EC 1.10.3.1). Phenol oxidizing enzymes which use hydrogen peroxide as electron acceptor are called peroxidases.
Phenol oxidizing enzymes can be utilised for a wide variety of applications, including the detergent industry, the paper and pulp industry (U.S. Pat. No. 4,690,895), the textile industry and the food industry. In the detergent industry, phenol oxidizing enzymes have been used for preventing the transfer of dyes in solution from one textile to another during detergent washing, an application commonly referred to as dye transfer inhibition.
For example, the use of peroxidases for bleaching fabrics during washing has been suggested in EP-A-424 398 (Novo Nordisk). WO-A-91/05839 (Novo Nordisk) describes the inhibition of dye transfer during the wash by means of peroxidase or an enzyme exhibiting oxidase activity on phenolic compounds. The compositions are said to bleach any dissolved textile dye so that no dye can redeposit upon the fabric.
It is also known that the activity of phenol oxidizing enzymes may be increased by the addition of certain organic compounds. The use of such activated enzyme systems for various purposes has also been described, for instance for inhibiting dye transfer in a washing process. The above mentioned WO-A-91/05839 (Novo Nordisk) describes that the addition of another oxidisable substrate may enhance the enzyme activity. Examples of such oxidisable substrates or “enhancers” are certain phenolic compounds, e.g. 2,4-dichlorophenol.
In three subsequent patent applications (WO-A-94/12619, WO-A-94/12620 and WO-A-94/12621, all Novo Nordisk) it is disclosed that the action of peroxidase in such anti dye-transfer compositions may be enhanced by the addition of a number of aromatic compounds, of which 2,2′-azo-bis-(3-ethylbenzo-thiazoline-6-sulphonate (ABTS) and Phenothiazine-10-propionate (PTP) appear to be the preferred compounds. WO-A-97/11217 (Novo Nordisk) discloses a process for bleaching stains by contacting the fabric in an aqueous medium with a phenol oxididizing enzyme and a “mediator”, which is preferably of the phenotiazine-type.
However, some of these aromatic enhancer compounds may not be attractive as ingredients of detergent compositions for economical or environmental reasons. Furthermore, some of these enhancers like ABTS are, in their oxidized form, dyestuffs themselves. This has the disadvantage that the washed fabrics may be coloured by residual amounts of oxidised ABTS.
WO-A-97/06244 (Ciba) discloses various other compounds as enhancers for phenol oxidizing enzyme such as substituted naphtols, barbituric acids, and substituted coumarins.
Thus, although some of these approaches have been successful to a certain extent, there is still a need for alternative or improved enhancers for the activity of phenol oxidizing enzymes. In particular, there is a need for effective enzymatic bleach compositions, e.g. enzymatic bleaching detergent compositions. It is therefor an object of the present invention to provide such effective alternative or improved phenol oxidizing enzyme enhancers and enzymatic bleach compositions containing them.
We have now surprisingly found that these and other objects can be achieved by using certain N-containing compounds as phenol oxidizing enzyme enhancers.
DEFINITION OF THE INVENTION
According to a first aspect of the invention, there is provided a process for enhancing the activity of a phenol oxidizing enzyme, comprising adding to the enzyme, as an enhancer for the activity of said enzyme, one or more compounds having the formula:
wherein:
A is an optionally substituted electron-withdrawing group, chosen from the group consisting of nitrile, carboxyl, and esters and salts thereof, amides, aldehydes, ketones, sulfoxides, sulfones, or sulphonates, and
B is an optionally substituted electron-donating group, chosen from the group consisting of the oxide anion, sulfide anion, oxides, amines, imines, hydroxides, sulfides, ethers, carboxylic acids, and halogen substituents, and
R
1
-R
5
may each independently represent hydrogen, hydroxy, halogen, nitroso, formyl, carboxyl, and esters and salts thereof, carbamoyl, sulfo, and esters and salts hereof, sulfamoyl, nitro, amino, phenyl, C
1
-C
20
alkyl, C
1
-C
8
alkoxy, carbonyl-C
1
-C
6
-alkoxy, aryl-C
1
-C
6
-alkyl, and R
2
and R
5
together may form an alkylene group or an alkenylene group.
According to a second aspect, there is provided an enzymatic bleach composition comprising a phenol oxidizing enzyme and an enhancer, as shown above. According to a third aspect, there is provided a detergent composition comprising the enzymatic bleach composition and which additionally comprises one or more surfactants. According to a fourth aspect, there is provided a process for bleaching stains on fabrics.
DESCRIPTION OF THE INVENTION
A first aspect of the invention is a process for enhancing the activity of a phenol oxidizing enzyme by adding to the enzyme, certain specific compounds which are capable of enhancing the activity of said phenol oxidizing enzyme, the so-called “enhancers”. A second aspect of the invention is formed by enzymatic bleach compositions comprising a phenol oxidizing enzyme and said enhancers.
(a) The Phenol Oxidizing Enzyme
The enzymatic bleach compositions according to the invention comprise, as a first constituent, a phenol oxidizing enzyme. A phenol oxidizing enzyme is defined for the purpose of the present invention as an enzyme or a system in which an enzyme, by using hydrogen peroxide or molecular oxygen, is capable of oxidising organic compounds containing phenolic groups. Examples of such enzymes are peroxidases and oxidases. Suitable enzymes are disclosed in EP-A-495 835 (Novo Nordisk). For instance, suitable peroxidases may be isolated from and are producible by plants or micro-organisms such as bacteria or fungi. Preferred fungi are strains belonging to the class of the Basidiomycetes, in particular Coprinus, or to the class of Hyphomycetes, in particular Arthromyces, especially
Arthromyces ramosus.
Other preferred sources are Hormographiella sp. or Soybean peroxidase. Other relevant peroxidases are haloperoxidases (U.S. Pat. No. 4,397,192) such as chloride peroxidases, bromide peroxidases and iodide peroxidases. Other potential sources of useful peroxidases are listed in B. C. Saunders et al., Peroxidases, London, 1964, pp 41-43.
In the context of this invention, phenol oxidizing enzymes which use oxygen as the oxidant, comprise any laccase comprised by the enzyme classification (EC 1.10.3.2), any catechol oxidase enzyme comprised by the enzyme classification (EC 1.10.3.1), any bilirubin oxidase enzyme comprised by the enzyme classification (EC 1.3.3.5) or any monophenol monooxygenase enzyme comprised by the enzyme classification (EC 1.14.99.1). The phenol oxidizing enzymes are known from microbial and plant origin. The microbial phenol oxidizing enzyme may be derived from bacteria or fungi (including filamentous fungi and yeasts) and suitable examples include a phenol oxidizing enzyme derivable from a st
Breel Greta Johanna
Convents Daniel
Swarthoff Ton
Twisker Robin Stefan
Van Liemt Willem
Mitelman Rimma
Prats Francisco
Srivastava K. C.
Unilever Home & Personal Care division of Conopco, Inc.
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