Lambeir A M, Opperdoes F R, Wierenga R K
International Institute of Cellular and Molecular Pathology, Research Unit for Tropical Diseases, Brussels, Belgium.
Eur J Biochem. 1987 Oct 1;168(1):69-74. doi: 10.1111/j.1432-1033.1987.tb13388.x.
The kinetic properties of Trypanosoma brucei brucei triose-phosphate isomerase are compared with those of the commercially available rabbit muscle and yeast enzymes and with published data on the chicken muscle enzyme. With glyceraldehyde 3-phosphate as substrate Km = 0.25 +/- 0.05 mM and kcat = 3.7 X 10(5) min-1. With dihydroxyacetone phosphate as substrate Km = 1.2 +/- 0.1 mM and kcat = 6.5 X 10(4) min-1. The pH dependence of Km and Vmax at 0.1 M ionic strength is in agreement with the results published for the yeast and chicken muscle enzymes. At ionic strength below 0.05 M the effect of a charged group specific for the trypanosomal enzyme and absent from the yeast and rabbit muscle enzymes becomes detectable. This effect significantly increases Km whereas Vmax becomes slightly higher. Trypanosomal triose-phosphate isomerase is inhibited by sulphate, phosphate and arsenate ions, by 2-phosphoglycolate and a number of documented inhibitors in the same concentration range as are the other triose-phosphate isomerases. The trypanocidal drug, Suramin inhibits T. brucei and rabbit muscle triose-phosphate isomerase to the same extent while leaving the yeast enzyme relatively unaffected.
将布氏布氏锥虫磷酸丙糖异构酶的动力学特性与市售的兔肌肉和酵母酶以及已发表的鸡肌肉酶的数据进行了比较。以3-磷酸甘油醛为底物时，Km = 0.25±0.05 mM，kcat = 3.7×10⁵ min⁻¹。以磷酸二羟丙酮为底物时，Km = 1.2±0.1 mM，kcat = 6.5×10⁴ min⁻¹。在0.1 M离子强度下，Km和Vmax对pH的依赖性与已发表的酵母和鸡肌肉酶的结果一致。在离子强度低于0.05 M时，锥虫酶特有的一个带电基团（酵母和兔肌肉酶中不存在）的作用变得可检测到。这种作用显著增加了Km，而Vmax略有升高。锥虫磷酸丙糖异构酶受到硫酸根、磷酸根和砷酸根离子、2-磷酸乙醇酸以及一些已记录的抑制剂的抑制，其浓度范围与其他磷酸丙糖异构酶相同。杀锥虫药物苏拉明对布氏锥虫和兔肌肉磷酸丙糖异构酶的抑制程度相同，而对酵母酶的影响相对较小。
