Invertase activity in Streptococcus mutans and Streptococcus sanguis

Abstract Toluene treatment of intact cells revealed invertase-like activity in Streptococcus mutans K1-R (cariogenic) and in Streptococcus sanguis 903–1600 (noncariogenic). The activity was identified as a β- d -fructofuranoside fructohydrolase (invertase; EC. 3.2.1.26) by its hydrolysis of sucrose and raffinose and its failure to act on melezitose and other glucoside derivatives. The invertase was induced by sucrose in Strep, sanguis but was a constituent in Strep. mutans. Amylomaltase, a transferase acting on maltosaccharide, was also detected in both organisms.