Extracellular dextranase from Streptococcus oralis

Area of Science:

• Microbiology
• Enzymology
• Biochemistry

Background:

• Dental plaque harbors various microorganisms, including Streptococcus oralis (S. mitior).
• Bacterial enzymes like dextranases play a role in the structure and metabolism of dental plaque.
• Understanding these enzymes is key to addressing plaque-related oral health issues.

Purpose of the Study:

• To isolate and characterize the dextranase enzyme produced by Streptococcus oralis.
• To determine the purification level, yield, and basic biochemical properties of the enzyme.

Main Methods:

• Cultivation of Streptococcus oralis in a specialized medium.
• Isolation of extracellular dextranase activity from the culture supernatant.
• Purification using sequential anion exchange and gel filtration Fast Protein Liquid Chromatography (FPLC).
• Analysis of enzyme properties including pH optimum, molecular mass, and amino acid composition.

Main Results:

• Dextranase activity was successfully isolated from the cell-free supernatant of Streptococcus oralis.
• The enzyme was purified 1,126-fold with a 2.4% yield.
• The purified dextranase is extracellular, constitutive, has an optimum pH of 6, and a molecular mass of 45 kD.
• Amino acid analysis indicated a high content of alanine and acidic amino acids.

Conclusions:

• A constitutive extracellular dextranase was purified from Streptococcus oralis.
• The enzyme's properties suggest its potential role in dextran metabolism within dental plaque.
• Further research is needed to elucidate the structural and biochemical impact of bacterial glucanases in human dental plaques.