KINETIC-PROPERTIES OF FRUCTOSE BISPHOSPHATE ALDOLASE FROM TRYPANOSOMA-BRUCEI COMPARED TO ALDOLASE FROM RABBIT MUSCLE AND STAPHYLOCOCCUS-AUREUS
KINETIC-PROPERTIES OF FRUCTOSE BISPHOSPHATE ALDOLASE FROM TRYPANOSOMA-BRUCEI COMPARED TO ALDOLASE FROM RABBIT MUSCLE AND STAPHYLOCOCCUS-AUREUS
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DOI：
10.1016/0166-6851(91)90142-s
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发表时间：
1991-07-01
影响因子：
1.5
通讯作者：
OPPERDOES, FR
中科院分区：
文献类型：
--
作者：
CALLENS, M;KUNTZ, DA;OPPERDOES, FR
研究了布鲁氏锥虫醛缩酶的动力学性质，并与兔肌肉和金黄色葡萄球菌的醛缩酶进行了比较。3种酶裂解1，6-二磷酸果糖(Fru(1，6)P2)的最适pH和裂解1-磷酸果糖(Fru-1-P)的最适pH值相近。然而，在更极端的pH值下，最大切割速率的微小变化会导致pH曲线之间的差异。布鲁氏葡萄球菌和金黄色葡萄球菌的醛缩酶催化的反应按照兔肌肉酶所描述的顺序进行。我们测定了这三种酶的裂解和形成Fru(1，6)P2以及裂解Fru-1-P的动力学参数。锥体酶的不同之处在于其最大Fru1，6-P2-裂解速率与Fru1-P2-形成最大速率之比较高，对二羟丙酮磷酸的亲和力较高，以及对Fru1-P裂解的周转数较高。当离子强度大于0.1M时，锥虫酶的动力学参数服从德拜-休克尔方程的极限形式。当离子强度低于0.1M时，该酶对Fru(1，6)P2的表观K(M)随盐浓度降低而增大。腺嘌呤核苷酸和磷酸盐竞争性地抑制锥虫体缩醛酶。这种抑制作用发生在与兔肌肉酶相同的浓度范围内，而细菌酶受到的影响较小。
The kinetic properties of aldolase from Trypanosoma brucei were studied in comparison with aldolase from rabbit muscle and Staphylococcus aureus. The 3 enzymes displayed a similar broad pH optimum for the cleavage of fructose 1,6-bisphosphate (Fru(1,6)P2) and a similar narrow pH optimum for the cleavage of fructose 1-phosphate (Fru-1-P). However, small alterations in the maximal cleavage rate at more extreme pH values yielded disparities between the pH curves. The reaction catalyzed by the aldolases from T. brucei and S. aureus proceeded via an ordered sequence, as described for the rabbit-muscle enzyme. We determined for the 3 enzymes the kinetic parameters for both the cleavage and the formation of Fru(1,6)P2 and for the cleavage of Fru-1-P. The trypanosomal enzyme differed in its higher ratio of the maximal rate of Fru(1,6)P2-cleavage vs. the maximal rate of Fru(1,6)P2-formation, its higher affinity towards dihydroxyacetone phosphate, and its higher turnover number for the cleavage of Fru-1-P. At ionic strengths above 0.1 M the kinetic parameters of the trypanosomal enzyme followed the limited form of the Debye-Huckel equation. At ionic strengths below 0.1 M the enzyme revealed a characteristic deviation: the apparent K(m) for Fru(1,6)P2 increased with decreasing salt concentration. The trypanosomal aldolase was competitively inhibited by adenine nucleotides and phosphates. This inhibition occurred in the same concentration range as observed for the rabbit-muscle enzyme, while the bacterial enzyme was less affected.