Hulea S A, Arnstein H R
Biochim Biophys Acta. 1977 May 17;476(2):131-48. doi: 10.1016/0005-2787(77)90090-9.
Five ribonuclease activities, separable by polyacrylamide gel electrophoresis, have been detected in erythroid bone marrow cells from anaemic rabbits. Their intracellular distribution has been investigated and compared with that of the ribonucleases in reticulocytes. Both the acid and alkaline ribonuclease activities of reticulocytes are much lower (30--50 fold) than those of bone marrow erythroid cells. The most marked decrease in enzyme activity occurs in the fractions containing ribosomes and mitochondria plus lysosomes. In these subcellular organelles there was also a qualitative change in the ribonuclease electrophoretic pattern, whereas the cytosol enzymes of marrow erythroid cells and reticulocytes remained largely unchanged. Several ribonucleases released from reticulocyte membranes with urea were similar to those present in the lysosomal plus mitochondrial fraction, as shown by detection of enzyme activity after polyacrylamide gel electrophoresis. The decline in ribonuclease activity was found to begin in the orthochromatic cells, which have a highly condensed nucleus and are no longer active in DNA and RNA synthesis, and to coincide with a decrease in acid phosphatase activity and loss of lysosomes.
在贫血兔的红细胞生成骨髓细胞中检测到了五种可通过聚丙烯酰胺凝胶电泳分离的核糖核酸酶活性。研究了它们在细胞内的分布，并与网织红细胞中的核糖核酸酶分布进行了比较。网织红细胞的酸性和碱性核糖核酸酶活性均远低于骨髓红细胞生成细胞（低30至50倍）。酶活性下降最明显的部分是含有核糖体以及线粒体加溶酶体的部分。在这些亚细胞器中，核糖核酸酶的电泳图谱也发生了质的变化，而骨髓红细胞生成细胞和网织红细胞的胞质溶胶酶基本保持不变。如聚丙烯酰胺凝胶电泳后酶活性检测所示，用尿素从网织红细胞膜释放的几种核糖核酸酶与溶酶体加线粒体部分中的核糖核酸酶相似。发现核糖核酸酶活性的下降始于正染细胞，这些细胞的细胞核高度浓缩，不再活跃于DNA和RNA合成，且与酸性磷酸酶活性的降低和溶酶体的丧失同时发生。
