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KMID : 0903519770200010033
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Journal of the Korean Society of Agricultural Chemistry and Biotechnology
1977 Volume.20 No. 1 p.33 ~ p.42
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Asparagine Biosynthesis in Soybean Sprouts
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Abstract
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Asparagine biosynthesis by soybean sprouts grown under the dark conditions has been demonstrated. The amount of free asparagine synthesized in ten day-old soybean sprouts. increases to 22.7 on the dry weight base. The effects of nitrogen compounds such as NH₄Cl, (NH₄)₂SO₄ and urea on asparagine synthesis during the sprouting were examined and the results showed that urea was more effective than other two compounds.
Glutamine-dependent asparagine synthetase was partially purified (8.6 folds) through ammonium sulfate fractionation, followed by Sephadex G-150 gel filtration. The enzyme was very labile and required protection by thiol groups or high level of glycerol. The mixture of ATP and Mg^(++) ion also stabilized the enzyme activity.
The enzyme utilized glutamine more effectively than NH₄^+ as an amide donor for the formation of asparagine. The enzyme required L-aspartate (Km=3.1 mM), L-glutamine, ATP and Mg^(++). It showed pH optimum of 7.5 and catalyzed the formation of β -aspartyl hydroxamate in the presence of L-aspartate, ATP, Mg^(++) and NH₂OH in the reaction mixture.
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