第7卷‧第2期,
198304
, pp. 158-164
固定化鳳梨?及木瓜?之動力學與熱力學性質
- 作者:
蕭介夫; 鄭寶樹
- 作者服務機構:
中央研究植物研究所; 國立高雄師範學院化學系
- 中文摘要:
所有PVC固定化鳳梨?與木瓜?均比其溶性酵素有較低之比活性,較高之Km值,較高之最適PH值,較高之活化
焓 (△H*)及活化自由能(△F*),較高之活化能(Ea)及較小之負活化熵 (AS*)。這些參數受到固定化過程所用之活化劑及
二胺物質鏈長度影響很大。
戌二醛固定化之鳳梨?與木瓜?均較溴化氰法固定之酵素有較小Km偏差,較大之酪蛋白分解反應之負△S*及較大
之熱變性反應正△S*值。戌二醛固定化之鳳梨?較溴化氰法固定者有較高之比活性,但固定化木瓜?則正好相反。
具有較長連接鏈之固定化鳳梨?與木瓜?均有較高之比活性,較小之Km最適PH偏差。然而連接鏈長度對△S*無
影響。
活化劑造成之影響可能為酵素構形之差異,可由△S*值變化反映出,而連接鏈長度之效應可能是由於基質擴散之立
體阻礙。
- 英文摘要:
Bromelain and papain immobilized on PVC showed decreased specific activities, higher Km, higheroptimal pH, higher activation enthalpy(△H*) and activation free energy (△F*), higher energy of activa-tion (Ea) and less negative activation entropy (△S*) than their respective soluble enzymes. These para-meters were greatly influenced by the activating reagents and the chain length of diamine compoundsused in the immobilization process. The glutaraldehyde immobilized proteases had smaller deviation of Km, higher negative △S* forcaseinolytic reaction and higher positive △S* for thermal denaturation than the cyanogen bromide coupledcounterparts for both papain and bromelain. Glutaraldehyde produced immobilized bromelain of higherspecific activity than cyanogen bromide coupled enzyme, however, the situation in immobilized papainwas the reverse. Both immobilized enzymes with longer chain length of connecting arm had greater relative specificactivity, smaller deviation of Km and optimal pH from soluble forms. However, the arm length had noeffect on △S*. The activating reagent effect was possibly due to conformational difference as reflected in changesof △S* and the arm length effect possibly arised from steric hindrance for substrate diffusion.
- 中文關鍵字:
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- 英文關鍵字:
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