Chemistry: molecular biology and microbiology – Enzyme – proenzyme; compositions thereof; process for... – Hydrolase
Patent
1997-01-30
1999-06-22
Weber, Jon P.
Chemistry: molecular biology and microbiology
Enzyme , proenzyme; compositions thereof; process for...
Hydrolase
C12N 962
Patent
active
059142596
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to aminopeptidases, their production and their industrial use.
Hydrolysis of proteins is of great importance, particularly in the food industry. It generally consists in transforming high molecular weight proteins (e.g. casein, gluten, gelatin, soy protein) into small fragments (oligopeptides or amino acids). These transformations may be carried out under highly acidic or highly alkaline conditions, which can often be energy consuming and requires the use of aggressive chemicals.
Protein degrading enzymes are preferred because they are less polluting and capable of working under mild conditions which prevents racemization of amino acids. These enzymes are classified into endoproteases and exopeptidases. Endoproteases cleave high molecular weight proteins into oligopeptides, whereas exopeptidases release amino acids from high molecular weight proteins or protein fragments.
Both types of enzyme are generally necessary to produce protein hydrolysates. The endo/exo ratio has to be varied according to the application. To obtain a strong liquefaction of a complex protein, endo enzymes are required to provide the major hydrolysis contribution. Conversely, to produce specific amino acids or peptides from a complex protein without destroying its physical properties (elasticity, foaming property, texture property) exo enzymes with low endo activity will be preferred.
Many microorganisms are able to produce endoprotease and exopeptidases. The endo/exo ratio is mainly dependent on culture conditions (1-3) and on downstream processing (4).
In the food industry, Aspergilli have been widely used for a long time and are therefore easily in conformity with regulations in many countries all over the world. Among Aspergilli, Aspergillus niger is the most widely used species in the food industry. Whereas endoprotease (5-7) and carboxypeptidase (8-10) from Aspergillus niger have been described, the production of aminopeptidase from Aspergillus niger has up to now not been known.
The present invention discloses aminopeptidases from selected Aspergillus niger strains and a method for producing them from appropriate cultures of Aspergillus niger. These aminopeptidases have an optimal activity at a pH in the range 6-8 and at a temperature in the range 50-60.degree. C. Moreover, under appropriate culture conditions, aminopeptidases can be produced by selected Aspergillus niger strains substantially free of endoprotease. By "substantially free of endoprotease" is meant without detectable, or at least without a substantial amount of, endoprotease. Thus, surprisingly, it has been found that by culturing selected Aspergillus niger strains, a fermentation broth filtrate or liquid concentrate thereof can be obtained containing small amounts of endoprotease, but containing a high amount of aminopeptidase activity. Thus, a cell-free preparation of Aspergillus niger aminopeptidase may, for example, advantageously have at least 10 times more aminopeptidase activity, preferably at least 30 times more aminopeptidase activity, than endoprotease activity.
In view of recent changes in the nomenclature of black Aspergilli, the term Aspergillus niger is herein defined as including all (black) Aspergilli that can be found in the Aspergillus niger Group as defined by Raper and Fennell (1965, In: The Genus Aspergillus, The Williams & Wilkins Company, Baltimore, pp 293-344). Similarly, also for the other Aspergillus species we will refer to the Aspergillus groups as defined by Raper and Fennell supra, thereby including all species and variants included in a particular group by these authors.
A phenylalanine-aminopeptidase (Phe-AP) and a leucine-aminopeptidase (Leu-AP) have been identified and characterised in such preparations, the phenylalanine-aminopeptidase making the major contribution to the total aminopeptidase activity. It will be appreciated, however, that the invention also extends to preparations of functional derivatives of Aspergillus niger aminopeptidases substantially free of endo
REFERENCES:
patent: 3660236 (1972-05-01), Dworschack et al.
patent: 3975544 (1976-08-01), Kosikowski
patent: 4708876 (1987-11-01), Yokoyama et al.
Bosmann, H.B. Biochim Biophys, Acta (1973) 293:476-489.
Castaneda, R. et al.Neth Milk Dairy J (1990) 44(2):49-64.
Dal Degan, F. et al. Appl Environm Microb (1992) 56:2144-2152.
Hayashi, K. et al. J Jpn Soc Food Sci Technol (1990) 37(9);737-739.
Koaze, Y. et al. Agr Biol Chem (1964) 28(4):216-223.
Kumagai, I. et al. Biochim Biophys, Acta (1981) 659:334-343.
Kumagai, I. et al. Biochim Biophys , Acta (1981) 659:344-350.
Labbe J. et al. "Action de leucine aminopeptidase I et II extracellulaire d'Aspergillus oryzae," Experientia31(8):886-887.Aug. 15, 1979.
Nakadai, T. et al. "Leucine aminopeptidase II,"Chemical Abstracts 85(17):484; No. 121827 Oct. 258, 1976.
Stevens, L. et al. Revue roumaine de Biochimie (1981) 18(1):63-66.
Stevens, L. Biochem Soc Trans (1985) 13(2):283-285.
Turkova, J. et al. J. Biochim Biophys Acta (1976) 420(2):309-315.
Brunet Jacky
Chevalet Laurent
De Leseleuc Joel
Souppe Jerome
Warmerdam Martinus J.M.
Gist-Brocades B.V.
Weber Jon P.
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