Protective Actions of l-Aspartate from Acid or Proteolytic Inactivation |
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Authors: | Nobuo Nakamura |
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Institution: | Tokyo Research Laboratory, Kyowa Hakko Kogyo Co., Ltd., Asahi-machi, Machida, Tokyo |
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Abstract: | l-Aspartate was found to replace l-asparagine in the protective action from acid inactivation of l-asparaginase (EC 3.5.1.1) produced by Escherichia coli A–1–3 and at the same time to inhibit the proteolytic inactivation by α-chymotrypsin. l-Asparaginase changed in its chromatographic properties in the presence of l-aspartate and became to be absorbed on the CM Sephadex column. The sedimentation patterns of l-asparaginase at pH 3.5 were identical either in the presence or absence of l-aspartate, showing partial dissociation. But the reversibility to the active state was observed only in the enzyme dissolved in the solution containing l-aspartate. l-Aspartate did not prevent the enzyme either from the dissociation into subunits or from decrease in the activity by urea. High concentration of l-aspartate was shown to inhibit the l-asparagine hydrolysis reaction. l-Aspartate was suggested from ORD measurements to cause changes in the higher structure as well as the ionic properties or proteolytic inactivation.
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Keywords: | apoptosis caspase normal lymphocytes tryptophol U937 |
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