Which enzyme catalyzes the conversion of glucose to dextran in Streptococcus mutans?

Which enzyme catalyzes the conversion of glucose to dextran in Streptococcus mutans?

• A. Amylase
• B. Lactase
• C. Glucosyltransferase
• D. Protease

Answer: (C)

Streptococcus mutans builds a sticky glucan, dextran, by linking glucose units into a long polymer. The enzyme that does this is glucosyltransferase, which catalyzes the transfer of glucose residues to a growing glucan chain to form dextran. This extracellular dextran helps the bacteria adhere to tooth surfaces and to each other, strengthening biofilm formation and contributing to cariogenic plaque. Amylase would break down starch, lactase breaks lactose, and protease degrades proteins, so they don’t create dextran.

Streptococcus mutans builds a sticky glucan, dextran, by linking glucose units into a long polymer. The enzyme that does this is glucosyltransferase, which catalyzes the transfer of glucose residues to a growing glucan chain to form dextran. This extracellular dextran helps the bacteria adhere to tooth surfaces and to each other, strengthening biofilm formation and contributing to cariogenic plaque.

Amylase would break down starch, lactase breaks lactose, and protease degrades proteins, so they don’t create dextran.