第5卷‧第2期,
198104
, pp. 190-197
以親力試劑-氧化腺?酸修飾人體胎盤鹼性磷酯?
- 作者:
張固剛; 潘福; 葉美珍
- 作者服務機構:
國防醫學院生物化學系
- 中文摘要:
由Sigma公司購得之人體胎盤鹼性磷酯?(EC 3.1.3.1.)可經由電泳法達到純化目的。此?與過碘酸氧化之腺?酸
反應,?活性即迅速喪失。而活性喪失之速度與氧化腺?酸濃度之間呈現飽和關係,表示有?-氧化腺?酸複合物的生成
。此?專有的不競爭性抑制劑L-苯丙胺酸能保護部份?活性。相同濃度的氧化腺?也能與?反應,但速度較慢。氧化腺?
酸同時也是此?的基質,有金屬存在時,其磷酸基可被?水解。?與氧化腺?酸反應過程中,活性逐漸喪失,而基質的Km
值及修飾後之?在電場中的移動速度均隨之增加,同時在反應過程中看不見未修飾的?分子,表示所有?分子皆已參加反
應。我們的結果顯示此?的活性中心可能有離胺酸基參與基質的結合。
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- 英文摘要:
Commercial human placental alkaline phosphatase (EC 3.1.3.1.)has been purified to apparenthomogeneity by a one-step preparative electrophoresis. This enzyme was inactivated by periodateoxidizedAMP. The inactivation showed saturation kinetics and could be prevented by the uncompetitive inhibitorL-phenylalanine. Same concentration of oxidized adenosine also caused inactivation but at a much slowerrate. Oxidized AMP was also found to be a substrate for this enzyme. At different stages of inactivation,the residual activity showed an altered apparent Michaelis constant and electrophoretic mobility comparedwith the native enzyme, with no evidence for the presence of unmodified enzyme molecules. Our resultssupport a functional role for the lysyl residue of this enzyme.
- 中文關鍵字:
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- 英文關鍵字:
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