Purification and some properties of beta-fructofuranosidase I from Arthrobacter sp. K-1

Arthrobacter sp. K-1, isolated from soil, produces beta-fructofuranosidase. This enzyme preparation was separated into three fractions (I, II, and III) by butyl-Toyopearl 650 M column chromatography. The beta-fructofuranosidase I was purified to homogeneity by disc-electrophoresis after consecutive column chromatographies. The enzyme had a molecular weight of 52,000 by SDS-polyacrylamide gel electrophoresis and 51,000 by gel filtration with Ultrogel AcA 44, and an isoelectric point of 4.3. The enzyme was most active at pH 6.5-6.8 and at 55 degrees C and stable up to 45 degrees C at pH 6.5 for 30 min of incubation, and from pH 5.5 to 10.0 at 40 degrees C in 2 hr of incubation. This enzyme hydrolyzed sucrose, erlose, raffinose, fructosylxyloside, neokestose, and stachyose at the relative velocities of 100, 75, 61, 59, 54, and 11, but hardly hydrolyzed 1-kestose and nystose (less than 0.02).