• 作者： 白壽雄; 王敏卿; 楊廣衍
• 作者服務機構： 國防醫學院生化系; 榮民總醫院醫學研究部
• 中文摘要： 本文係研究生產青黴素醯化?（PA）菌種之篩選與培養，以及PA的製備、固化與一般性質。由篩選所得之大腸菌(E.
  coli)，以加苯乙酸之酵母精培養液，於適宜條件下培養，每公升約可得9公克之濕菌，每公克含780單位(μmoles/h)之
  PA活性。菌體經超音波搗碎後，以硫酸鏈黴素，硫酸銨，聚乙二醇等處理純化，約可得40％之PA產率；再經DEAE
  －纖維素層析，可得之最高PA比活性為每毫克蛋白質553單位。此純化之PA分別以幾丁質，CNBr-Sepharose 4B及
  XAD7樹脂作為固化擔體，則以XAD7最為適宜；其最高比活性每公克XAD7-PA（濕重）可達4300單位。
  PA以XAD7固化後，最適反應酸度，溫度及對基質的親和力均與未固化者相似，分別為8.0，55℃與2mM。
  固化後之最適反應磷酸?濃度為1OOmM，而未固化者之活性在10-300mM間均無明顯差異。熱安定性試驗顯示，XAD7
  固化之PA在不同溫度加熱2小時，則在30-65℃間時，其活性漸次下降，而未固化之PA則在37℃時仍不受影響，
  但在50℃時，活性完全消失。固化PA f 3個月低溫(5℃)貯存與12次之間歇活性測試後，仍保有88%活性，室溫時
  為66％，冷凍乾燥則活性幾乎完全消失。
  e
• 英文摘要： Penicillin acylase (PA) was induced and extracted from Escherichia coli GSM6 from our own col-lections, cultivated in phenyl acetate and yeast extract, and purified by frationation with streptomycinsulfate, ammonium sulfate and polyethylene glycol, followed by chromatography on DEAE-cellulose.The highest specific activity measured was about 553 units/mg, and overall purification yield was about40%. Immobilization studies revealed that Amberlite XAD7 resin was the best support for PA immobiliza-tion. The maximum specific activity obtained for the XAD7 immobilized PA was about 4,300 units/g(wet wt.). The optimal pH and temperature, and affinity to substrate (Km) were very similar between the freeand XAD7 immobilized PA (about 8.0, 55℃ and 2 mM respectively). The optimum buffer (phosphate)concentration for reaction was about 100 mM for the immobilized PA, while the activity of free PA wasnot significantly affected by the buffer concentration between 10 and 300 mM. The activity of free PAwas not affected by preheating at 37℃ for 2 h but the enzyme was inactivated at 50℃. The XAD7-PAlost its activity gradually after preheating between 30-65℃. The immobilized PA retained 88% of itsoriginal activity after storage at 5℃ for 3 months, and about 66% at room temperature. Its activity wasalmost totally lost on freeze-drying.
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