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Invertase Stabilization by Chemical Modification of Sugar Chains with Carboxymethylcellulose
Enzyme Technology Group, Center for Biotechnological Studies, University of Matanzas, Autopista a Varadero Km 31/2, Matanzas CP 44740, Cuba
Enzyme Technology Group, Center for Biotechnological Studies, University of Matanzas, Autopista a Varadero Km 31/2, Matanzas CP 44740, Cubavilla{at}cdict.umcc.cu
Polymer Materials Research Group, Department of Organic Chemistry, University of Gent, Krijgslaan 281 S-4, B-9000 Gent, Belgium Invertase from Saccharomyces cerevisiae was activated by periodate treatment and further reacted with ethylenediamine/sodium borohydride. Carboxymethylcellulose was then attached to ethylenediamine-modified invertase using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as coupling agent. The modified enzyme contained 3.5 mol of polysaccharide per mol of holoenzyme, and retained about 56% of the initial invertase activity. The thermostability of invertase increased from 64 to 70° C, the thermal inactivation at different temperatures ranging from 60 to 70° C was markedly reduced for polymer-modified enzyme. An increase of 9.1 kJ mol1 in activation free energy of inactivation was determined for invertase after modification. Functional stability was increased for carboxymethylcellulose-invertase complex in the range of pH between 2.0 and 12.0. The conjugate was also more resistant to denaturation by 6 M urea solution.
Journal of Bioactive and Compatible Polymers, Vol. 17, No. 3,
161-172 (2002) |
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