A protease derived from Bacillus species P7 digests a protein, called casein, that is found in ovine, or sheep's, milk. A study published in the May 2011 issue of the "Journal of the Science of Food and Agriculture" investigated the antioxidant and antimicrobial effects of partial casein proteins after p7 proteolysis, or splitting of the protein. The study found that the partial ovine caseinate inhibited the growth of several bacterial species. Additionally, the authors reported that the partial protein showed antioxidant activities.
All organisms produce proteases, which are enzymes that digest proteins by using water molecules to break bonds between amino acids in a process called hydrolysis. Proteases are important to protect cells and organisms from invading pathogens and for the breakdown of protein molecules for energy. Since the discovery of new Bacillus species is still ongoing at the time of this publication, the actions of most proteases have yet to be elucidated.
Bacillus anthrasis is the causative agent of anthrax, a lethal disease that affects humans and animals. Proteases from B. anthrasis are believed to have important roles in the progression of anthrax; however, none of these purported enzymes have yet to be fully described. A study in the May 2011 issue of "BMC Biochemistry" identified novel proteases derived from the B. anthrasis. The authors were able to identify the proteases by genetically modifying another bacterial species, Escherichia coli, so that they could mass produce the enzyme. The researchers were successful in expressing the anthrax proteases in E. coli and were able to purify the enzymes to uncover their chemical compositions. However, their biological activities are yet to be described.
The identification of proteases and their functions were first attempted in the late 1960s. In 1973, the "Journal of Molecular Biology" published an article that described the properties of a protease isolated from Bacillus subtillis, a common soil bacteria. The authors found that the protease from the species can exist either inside or outside of the organism, due to a single mutation activated by temperature. The paper went on to state that the protease is involved in the cleavage of an enzyme that unites amino acids in the production of RNA, called RNA polymerase. The polymerase molecule is responsible for the temperature-activated formation of spores, the reproductive forms of the bacteria.
A protease that cleaves a protein molecule at a serine amino acid residue was isolated from a newly discovered bacillus species named SSR1. An article appearing in the March 2001 issue of "Process Biochemistry" described the properties of the enzyme. The authors stated that it is a single protein, or monomer, and most active at a pH of 8 to 11, or in alkaline environments. The researchers also found that the enzyme is most active in the presence of metal ions, or charged atoms, such as iron, calcium and sodium. Other than its preferences for cutting a protein at a serine residue, little else is known about the molecule.
- "Process Biochemistry"; Serine Alkaline Protease from a Newly Isolated Bacillus sp. SSR1; J. Singh et al.; March 2001
- "Journal of Molecular Biology"; The Relationship of Serine Protease Activity to RNA Polymerase Modification and Sporulation in Bacillus subtilis; T. Leighton et al.; May 1973
- "BMC Biochemistry"; Recombinant Expression and Functional Analysis of Proteases from Streptococcus pneumoniae, Bacillus anthracis, and Yersinia pestis; K. Kwon et al.; May 2011
- "Journal of the Science of Food and Agriculture"; Antioxidant, Antihypertensive and Antimicrobial Properties of Ovine Milk Caseinate Hydrolyzed with a Microbial Protease; A. Correa et al.; May 2011
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