|Livingston, David - UNIV. OF NORTH CAROLINA|
Submitted to: Plant Physiology Supplement
Publication Type: Abstract Only
Publication Acceptance Date: April 26, 1995
Publication Date: N/A
Technical Abstract: A fructan hydrolase from stem bases of nonhardened oats was purified and partially characterized. Purification to homogeneity as judged by SDS-PAGE was achieved by ammonium sulfate precipitation and chromatography on anion exchange and hydrophobic interaction columns. The activity was maximal at pH 5.5. The denatured enzyme is 43 kD and the native enzyme is 53 kD. The enzyme is probably glycosylated as it binds ConA. Using fructans purified from oat stems, the enzyme was determined to hydrolyze the terminal beta-2,6 linkages of neokestose, (6G,6) nystose and (1&6G) nystose. Using (6G,6) nystose as the substrate, the Km was 5.6 percent and the Vmax 0.14 umol/min. The Km and Vmax for hydrolysis of a mixture of oat beta-2,6-fructans with DP 6-14 were 2.8 percent and 0.041 umol/min, respectively. Michaelis-Menten kinetics were observed with both substrates. The enzyme, which does not hydrolyze sucrose, hydrolyzes chicory inulin at less than 5 percent the rate at which it hydrolyzes a mixture of oat beta-2,6-fructans with DP 6-14.