猪甲状腺过氧化物酶的纯化及抑制物的实验研究

目的 提供一个简便的甲状腺过氧化物酶（TPO）的纯化方法，并研究其抑制物对酶活性的影响。方法 用差速离心、胰蛋白酶与去氧胆酸钠增溶、硫酸铵盐析及DE52、Sephadex G100和DEAE－Sephadex A50三步柱层析法从猪甲状遥中提纯TPO。比较不同浓度的氟化钠（NaF) 、硫氰化钾（KSCN）、丙基硫脲嘧啶（PTU）及叠氮钠（NaN3)对TPO活性的影响。结果 TPO提纯终产物的纯化倍数为298．6，其RZ值为0．27。N N3、PTU、KSCN和NaF抑制TPO活性，并且随着其浓度的升高，抑制作用增强，抑制常数分别为4．4，3．2，2．6和1．8。结论 提供的TPO纯化方法简便、可靠。NaN3、PTU、KSCN和NaF对TPO活性的抑制作用依次减弱。

Purification of porcine thyroid peroxidase and study of the inhibitors

Objective To purify thyroid peroxidase (TPO) from porcine thyroid tissue by an improved and simplified method and to study the effects of the inhibitors on activity of the enzyme.Methods The membrane- bound enzyme was solubilized by trypsin plus detergent. After precipitation with ammonium sulfate, the enzyme was purified by a series of column treatments, including ion-exchange chromatography on DEAE-cellulose, gel filtration through Sephadex G100 and DEAE-Sephadex A50 chromatography. We also compared the effects on activity of TPO with various concentrations of thiocyanide(KSCN), fluoride(NaF), azide(NaN 3) and propylthiouracil(PTU).Results The final product of purification had a value for RZ of 0.27 and for purified fold of 298.6. TPO was inhibitied by NaN 3, PTU, KSCN and NaF.With various inhibitory concentrations sigmoidal inhibition curves were obtained. The inhibition constants, obtained from the curves,were 4.4(NaN 3), 3.2(PTU), 2.6(KSCN) and 1.8(NaF).Conclusions The results suggest that the method of purification is improved and depended.The effects of the inhibitors on activity of TPO are lowered in order(NaN 3>PTU>KSCN>NaF).