Wozniewski, Th. and Blaschek, W. and Franz, Gerhard (1992) Isolation and Characterization of an Endo-ß-Mannase of Lilium testaceum Bulbs. Phytochemistry 31, pp. 3365-3370.
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The bulbs of Lilium testaceum contain large quantities of a storage β-1,4-glucomannan (β-1,4-GM) with a Man to Glc ratio of 7 to 3 and a Mr of 230 000. The mobilization of the β-1,4-GM as well as of the accompanying starch proceeds during germination of the Lilium bulbs. Enzymes responsible for the breakdown of the reserve polysaccharides were shown to be α-amylase, α-glucosidase, β-mannosidase, β-glucosidase and endo-β-mannanase. A crude enzyme preparation hydrolysing the Lilium GM was isolated from germinated Lilium bulbs and enzymes were separated by ion exchange chromatography (IEC) on DEAE-Sephacel and by gel permeation chromatography (GPC) on Superose™12. The purified β-mannanase exhibited optimal activity at pH 4.5 and an optimal temperature of 40°. The Mr of the β-mannanase was estimated to be 33 000 by gel filtration, the Km and Vmax values were 6.17 × 10−3 M and 16.1 × 10−3 nkat, respectively. The activity of the β-mannanase was determined by measuring the reduction of the viscosity and the enhancement of reductive equivalents in β-1,4-GM solutions. The GM-hydrolysis proceeded by a random mechanism. The β-1,4-GM degradation products were identified as Man, Glc, a number of β-1,4-manno- and glucomanno-oligosaccharides and a remarkable amount of a small Mr (3000) GM fraction with an identical Man to Glc ratio as in the genuine GM.
|Institutions:||Chemistry and Pharmacy > Institute of Pharmacy > Retired Professors > Prof. Franz|
|Keywords:||Lilium testaceum; Liliaceae; bulbs; glucomannan mobilization; endo-β-mannanase|
|Subjects:||500 Science > 540 Chemistry & allied sciences|
500 Science > 570 Life sciences
|Created at the University of Regensburg:||Unknown|
|Deposited On:||11 Nov 2011 11:15|
|Last Modified:||11 Nov 2011 11:15|