Proteolytic processing of dextransucrase of Leuconostoc mesenteroides

Area of Science:

• Enzymology
• Microbiology
• Protein Chemistry

Background:

• Dextransucrase preparations can contain various molecular mass forms.
• Proteolytic activity is a potential cause for these variations.
• Leuconostoc mesenteroides is a known producer of dextransucrase.

Purpose of the Study:

• To identify and characterize extracellular protease in Leuconostoc mesenteroides dextransucrase preparations.
• To investigate the effect of this protease on dextransucrase molecular mass and activity.

Main Methods:

• Enzyme purification and molecular mass determination (SDS-PAGE).
• Protease activity assays.
• Controlled hydrolysis of dextransucrase by purified protease under specific pH and temperature conditions.

Main Results:

• An extracellular protease with a molecular mass of 30 kDa was identified as the predominant form, originating from a larger precursor.
• Protease production and activity were highly pH-dependent.
• Hydrolysis of 173 kDa dextransucrase by the protease at pH 7 and 37°C generated active forms with molecular masses down to 120 kDa.

Conclusions:

• Extracellular protease activity contributes to the heterogeneity of dextransucrase molecular mass observed in enzyme preparations.
• The identified protease can generate functional, lower molecular mass dextransucrase variants.
• Understanding protease activity is crucial for controlling dextransucrase preparation characteristics.