Touster O, Aronson N N, Dulaney J T, Hendrickson H
J Cell Biol. 1970 Dec;47(3):604-18. doi: 10.1083/jcb.47.3.604.
Nucleotide pyrophosphatase and phosphodiesterase I of rat liver have been found to be localized primarily in cell particulates highly enriched with respect to the most commonly accepted plasma membrane marker, 5'-nucleotidase, and therefore should themselves be assigned a plasma membrane localization. The observation that plasma membranes sediment in isotonic sucrose with both nuclear and microsomal fractions was exploited to obtain plasma membrane preparations from each fraction. Both preparations are similar in chemical and enzymic composition. Moreover, the preparative method developed in this study appears to give the best combination of yield, purity, and reproducibility available. The question of the possible identity of nucleotide pyrophosphatase and phosphodiesterase I is considered, and evidence is presented suggesting that these activities may be manifestations of the same enzyme.
已发现大鼠肝脏中的核苷酸焦磷酸酶和磷酸二酯酶I主要定位于细胞颗粒中,这些颗粒相对于最普遍认可的质膜标志物5'-核苷酸酶高度富集,因此它们自身应被归为质膜定位。利用质膜在等渗蔗糖中与核组分和微粒体组分一起沉降的观察结果,从每个组分中获得质膜制剂。两种制剂在化学和酶组成上相似。此外,本研究中开发的制备方法似乎能提供产量、纯度和可重复性方面的最佳组合。文中考虑了核苷酸焦磷酸酶和磷酸二酯酶I可能相同的问题,并提供了证据表明这些活性可能是同一种酶的表现形式。