Chemistry: molecular biology and microbiology – Enzyme – proenzyme; compositions thereof; process for... – Hydrolase
Patent
1995-05-05
1998-08-11
Sisson, Bradley L.
Chemistry: molecular biology and microbiology
Enzyme , proenzyme; compositions thereof; process for...
Hydrolase
435183, 510114, 530324, 530350, C12N 942, C12N 900, A61K 3800, C07K 100
Patent
active
057926417
DESCRIPTION:
BRIEF SUMMARY
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of PCT/DK93/00327 filed Oct. 6, 1993, published as WO94/07998 Apr. 14, 1994, which is incorporated herein by reference and claims priority under .sctn. 119 to Danish patent application No. 1221/92, filed 6 Oct. 1992, 1222/92, filed 6 Oct. 1992, 1223/92, filed 6 Oct. 1992, 1224/92, filed 6 Oct. 1992, 1225/92, filed 6 Oct. 1992, 1513/92, filed 18 Dec. 1992, 1515/92, filed 18 Dec. 1992, and 1543/92, filed 23 Dec., 1992, all of which applications are incorporated herein by reference.
1. Field of Invention
The present invention relates to cellulase variants with improved properties.
2. Background of the Invention
Enzymes which are able to degrade cellulose (in the following termed "cellulolytic enzymes" or "cellulases") may be used in paper pulp processing for removing the non-crystalline parts of cellulose, thus increasing the proportion of crystalline cellulose in the pulp, and in animal feed for improving the digestibility of glucans. A further important use of cellulolytic enzymes is for textile treatment, e.g. for reducing the harshness of cotton-containing fabrics (cf., for instance, GB 1 368 599 or U.S. Pat. No. 4,435,307), for soil removal and colour clarification of fabrics (cf., for instance, EP 220 016) or for providing a localized variation in colour to give the fabrics a "stone-washed" appearance (cf., for instance, EP 307 564).
The practical exploitation of cellulolytic enzymes has, to some extent, been set back by the nature of the known cellulase preparations which are often complex mixtures of a variety of single cellulase components, and which may have a rather low specific activity. It is difficult to optimise the production of single components in multiple enzyme systems and thus to implement industrial cost-effective production of cellulolytic enzymes, and their actual use has been hampered by difficulties arising from the need to employ rather large quantities of the enzymes to achieve the desired effect.
The drawbacks of previously suggested cellulolytic enzymes may be remedied by using single-component enzymes selected for a high specific activity. Single-component cellulases are described in, e.g. WO 91/17243, WO 91/17244 and WO 91/10732.
SUMMARY OF THE INVENTION
Further investigations have now shown that improved properties of cellulases may be obtained by one or more specific mutations in the DNA sequence expressing a specific cellulase in order to obtain cellulase variants exhibiting such improved properties.
Accordingly, the present invention relates to a cellulase variant of a parent cellulase comprising a cellulose binding domain (CBD), a catalytically active domain (CAD) and a region linking the cellulose binding domain and catalytically active domain (the linking region), wherein, to improve the properties of the cellulase variant, one or more amino acid residues of the CBD, CAD or linking region is deleted or substituted by one or more amino acid residues and/or one or more amino acids are added to the linking region and/or another CBD is added at the opposite end of the catalytically active domain.
The cellulase variants of the present invention exhibit increased alkaline activity and increased compatibility with other ingredients usually present in detergent compositions such as powder compositions, liquid compositions and heavy duty liquid compositions.
Furthermore, the cellulase variants of the invention, when used in detergent compositions, have improved properties as regards particulate soil removal, colour clarification, defuzzing, depilling and harshness reduction, and they exhibit reduced sensitivity to anionic surfactants and reduced sensitivity to oxidation or the presence of a peroxidase bleaching system.
It is contemplated that the improved properties of the cellulase variants of the invention make the cellulase variants even more useful than the known cellulases e.g. when used in paper pulp processing, in animal feed, for textile treatment and for providing a "stone-washed" appearance o
REFERENCES:
patent: 4945053 (1990-07-01), Ito et al.
Chemical Abstracts, vol. 118, p. 358, 1993.
Abstract Japan 3240491.
Russell et al., Nature, vol. 328, pp. 496-500, 1987.
Estell et al., The Journal of Biological Chemistry, vol. 260, No. 11, pp. 6518-6521, 1985.
Fredholm Henrik
Hjorth Carsten Mailand
Nielsen Egon
Rasmussen Grethe
Rosholm Peter
Gregg, Esq. Valeta
Novo Nordisk A S
Sisson Bradley L.
Zelson Esq. Steve T.
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