1. Field of the Invention
The present invention relates to purified nucleic acids encoding antartic krill (Euphausia superba) derived enzymes such as proteinases, which can be a protein, and to purified polypeptides that have high proteolitytic activity and belong to the family of serine trypsin like enzymes. The present invention also relates to a protein having cold adapted activity, especially specific activity in the range of 4–50° C. In addition, the present invention relates to a DNA construct comprising a DNA sequence encoding the cold adapted trypsin protease, and a cell including the DNA construct. Furthermore, the present invention relates to a method of preparing the cold adapted trypsin protease by using recombinant DNA techniques.
2. Description of the Prior Art
The trypsin/chymotrypsin-like serine protease (S1) family plays roles in a multitude of diverse physiological processes, including digestive processes and regulatory amplification cascades through the proteolytic activation of inactive zymogen precursors, including its self activation. In addition to activating zymogen proteases, the trypsin/chymotrypsin-like serine protease can digest almost any protein with basic amino acids as part of its sequence and has thus become a common protein-chemistry reagent.
Trypsin proteases are used in numerous and varied industrial contexts and commercial purposes including laundry detergents, food processing, drugs, and skin care products. In laundry detergents, the protease is employed to break down organic or poorly soluble compounds to more soluble forms that can be more easily dissolved in detergent and water. Examples of food processing include tenderizing meats and maturing cheese. Proteases may be used in skin care field to remove scales on the skin surface that build up due to an imbalance in the rate of desquamation. In the case of drugs, several oral enzyme therapies that include trypsin as one component have shown promise in easing inflammation and in treating some cancers.
Common proteases used in some of these applications are derived from prokaryotic or eukaryotic cells that are easily grown for industrial manufacture of their enzymes. For example, a common species used is Bacillus as described in U.S. Pat. No. 5,217,878. Alternatively, U.S. Pat. No. 5,278,062 describes serine proteases isolated from a fungus, Tritirachium album, for use in laundry detergent compositions. The advent of recombinant technology allows expression of any species' proteins in a host suitable for industrial manufacturing. The majority of the commercially available proteases used in detergent application have high optimal temperatures, for example 60° C.
Other enzymes with cold adapted tripsin like activity and from vertebrates (Atlantic salmon, Antarctic fish, Atlantic cod and pufferfish) have been previously characterized (Schroder, H., Willassen, Nils., Smalas, Arne. (1999) Extremophiles 3:205–219). But all these proteins have high homology and low thermal stability at ambient temperatures.
Therefore, there is a need for a new protease, in this case trypsin-like protease, that works at ambient temperatures.