Purification and characterization of sucrose: sucrose 1-fructosyltransferase from the roots of asparagus (Asparagus officinalis L.).

Abstract

A sucrose: sucrose 1-fructosyltransferase has been highly purified from the extract of asparagus roots by successive chromatographies with DEAE-, CM-cellulose, Sephadex G-200 and sucrose-coupled Sepharose 6B. The disc-electrophoretically homogeneous enzyme (mol. wt. ca. 65,000), free from the activity of β-fructofuranosidase and other fructosyltransferases, catalyzes fructosyltransfer from sucrose producing 1-kestose and glucose. The reaction is reversible. The transferase also exhibits an activity of fructosyltransfer from sucrose to the fructose in the sucrose moiety of neokestose and its homologous 6G (1-β-fructofuranosyl)n-sucrose. The enzyme, however, does not catalyze fructosyltransfer to 1F (1-β-fructofuranosyl)n-sucrose and 1F (1-β-fructofuranosyl)m-6G (1-β-fructofuranosyl)n sucrose (except for m=0). Other properties of this enzyme are as follows: opt. pH, ca. 5.0; Km for sucrose, 0.11 m; stable on heating at 30°C, pH 4.0~8.0; labile (ca. 50% loss) on heating at 45°C, pH 5.0~6.5; inhibited by Hg2+...