Pectin transeliminase complex fromAspergillus flavus |
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Authors: | O Famurewa M A Oyede P O Olutiola |
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Institution: | (1) Department of Microbiology, Ondo State University, Ado-Ekiti, Nigeria;(2) Department of Microbiology, Obafemi Awolowo University, Ile-Ife, Nigeria |
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Abstract: | Aspergillus flavus grown in a liquid medium containing pectin as the sole carbon source produced extracellular enzymes which degraded the 1,4-α-d-glycosidic bonds of pectin. The products of degradation were characteristic of substances produced by transeliminase. Synthesis
of this enzyme was repressed by the addition of sucrose, glucose, fructose and maltose. The crude enzyme was partially purified
by a combination of ultrafiltration and ammonium sulfate precipitation. The partially purified enzyme was separated by molecular
exclusion chromatography into three components A, B and C, with molar masses ranging from 13.2 to 64 kDa. Only fraction B
exhibited enzymic activity and further fractionated by ion-exchange chromatography into four components I–IV. Among these
components, only fractions I and II possessed transeliminase activity. Both fractions had an optimum activity at pH 8.5 and
35°C, and were stimulated by Ca2+, Mg2+, Na+ and K+ but inhibited by EDTA and DNP. The apparentK
m for the degradation of pectin by fractions I and II were 6.2 and 8.0 g/L, respectively. |
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Keywords: | |
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