Minelli A, Moroni M, Trinari D, Mezzasoma I
Department of Cellular and Molecular Biology, University of Perugia, Italy.
Comp Biochem Physiol B Biochem Mol Biol. 1997 Aug;117(4):531-4. doi: 10.1016/s0305-0491(97)00213-7.
Ectoenzymic activities capable of hydrolyzing ATP sequentially to adenosine are present on equine epidydimal spermatozoa membranes. Kinetic parameters for ATPase, ADPase and 5'-nucleotidase were obtained by analysis of progress reactions curve when ATP, ADP and AMP were supplied as initial substrates. These values are not different from those found when the substrates were supplied from the preceding reactions. Feed-forward inhibition on 5'-nucleotidase by ATP/ADP was taken into account to fit simulated data to the experimental results. None of the substrates supplied by the preceding reactions showed a preferential delivery to ADPase and/or 5'-nucleotidase. We therefore conclude that the model that fits the equine spermatozoa is that already proposed for pig aortic endothelial cells.
马附睾精子细胞膜上存在能够将ATP依次水解为腺苷的外酶活性。当以ATP、ADP和AMP作为初始底物时，通过分析反应进程曲线获得了ATP酶、ADP酶和5'-核苷酸酶的动力学参数。这些值与从前一反应提供底物时得到的值没有差异。考虑到ATP/ADP对5'-核苷酸酶的前馈抑制作用，以使模拟数据与实验结果相拟合。前一反应提供的底物均未显示出对ADP酶和/或5'-核苷酸酶的优先递送。因此，我们得出结论，适用于马精子的模型是已经为猪主动脉内皮细胞提出的模型。
