Purification and some properties of fructan: fructan fructosyl transferase from dandelion (Taraxacum officinale Weber)

Abstract
A fructan: fructan fructosyl transferase (FFT, EC 2.4.1.100) was purified 61-4-fold from roots of Taraxacum officinale Weber. The enzyme is a glycoprotein with an apparent molecular weight of 49000 as determined by SDS-polyacrylamide gel electrophoresis. FFT activity was detected by 1-kestose-dependent nystose production. The enzyme was most active at pH 6·5 and was stable at 30°C (1 h). Separation by preparative iso-electric focusing yielded four different forms with iso-electric points around pH 4·8. The purified enzyme was active on different oligofructans of the inulin series, but not on melezitose, 6-kestose, neokestose, maltopentaose or sucrose as the sole substrate.