克氏锥虫中的高亲和力钙刺激、镁依赖性三磷酸腺苷酶

High-affinity calcium-stimulated, magnesium-dependent adenosine triphosphatase in Trypanosoma cruzi.

Cataldi de Flombaum M A, Stoppani A O

Departamento de Química Biológica, Facultad de Medicina, Buenos Aires, Argentina.

Comp Biochem Physiol B. 1992 Dec;103(4):933-7. doi: 10.1016/0305-0491(92)90218-g.

Abstract

A high-affinity (Ca2+ + Mg2+)-ATPase and a low-affinity Mg(2+)-ATPase were identified in the 105,000 g fraction from epimastigote forms of Trypanosoma cruzi, the agent of Chagas' disease (Tulahuen strain). 2. Activities were conserved after enzyme solubilization with deoxycholate. 3. The Ca(2+)-stimulated ATPase activity was (a) lower than that of the Mg(2+)-ATPase; (b) inhibited by p-chloromercurobenzoate and orthovanadate and (c) insensitive to oligomycin. 4. Optimal stimulation by Ca2+ was observed at pH 6.5-6.8 in the presence of 1 mM MgCl2 and 0.1 M KCl. 5. The Mg(2+)-ATPase was insensitive to p-chloromercurobenzoate and orthovanadate and did not require KCl for activity. 6. Kinetic analysis of the (Ca2+ + Mg2+)-ATPase yielded a half-maximal stimulating concentration of 1.1 microM for Ca2+ and a Km of 66 microM for ATP. 7. The (Ca2+ + Mg2+)-ATPase clearly differed from the Ca(2+)- or Mg(2+)-ATPases previously characterized in the same strain of T. cruzi (Frasch et al., 1978; Comp. Biochem. Physiol. 60B, 271-275).

摘要

在恰加斯病病原体克氏锥虫（图拉温株）的副鞭毛体形式的105,000 g组分中鉴定出一种高亲和力（Ca2+ + Mg2+）-ATP酶和一种低亲和力Mg(2+)-ATP酶。2. 用脱氧胆酸盐溶解酶后，活性得以保留。3. Ca(2+)-刺激的ATP酶活性（a）低于Mg(2+)-ATP酶的活性；（b）被对氯汞苯甲酸和原钒酸盐抑制，且（c）对寡霉素不敏感。4. 在1 mM MgCl2和0.1 M KCl存在下，在pH 6.5 - 6.8时观察到Ca2+的最佳刺激作用。5. Mg(2+)-ATP酶对对氯汞苯甲酸和原钒酸盐不敏感，且活性不需要KCl。6. 对（Ca2+ + Mg2+）-ATP酶的动力学分析得出，Ca2+的半最大刺激浓度为1.1 microM，ATP的Km为66 microM。7. （Ca2+ + Mg2+）-ATP酶明显不同于先前在同一株克氏锥虫中鉴定的Ca(2+)-或Mg(2+)-ATP酶（Frasch等人，1978年；《比较生物化学与生理学》60B，271 - 275页）。