Wiederanders B, Ansorge S, Bohley P, Broghammer U, Kirschke H, Langner J
Acta Biol Med Ger. 1976;35(3-4):269-83.
The preparation and properties of cathepsin D from rat liver are reported. The enzyme is an endopeptidase of lysosomal origin. The molecular weight was estimated to be 49000 by sodium-dodecylsulfate electrophoresis. We did not find any dissociation into subunits under reducing conditions, in contrast to some other authors. We found the enzyme to occur in at least 4 forms with the isoelectric points 5.87, 5.65, 5.41 and 5.13. Strong -SH-blocking reagents inhibit the activity, but the most powerful and specific inhibitor was pepstatin (Ki=38 nM). The substrate specificity is discussed. There was no proof for any zymogen activation in a great number of experiments. Since the cathepsins B1, B3 and L obviously seem to play the major role in the intracellular protein breakdown within the rat liver, the main task of cathepsin D is the degradation of extracellular proteins in this organ.
本文报道了从大鼠肝脏中制备组织蛋白酶D及其性质。该酶是一种溶酶体来源的内肽酶。通过十二烷基硫酸钠电泳估计其分子量为49000。与其他一些作者不同，我们发现在还原条件下该酶不会解离成亚基。我们发现该酶至少以4种形式存在，其等电点分别为5.87、5.65、5.41和5.13。强-SH阻断剂会抑制其活性，但最有效且特异的抑制剂是胃蛋白酶抑制剂（Ki = 38 nM）。文中讨论了底物特异性。在大量实验中未发现任何酶原激活的证据。由于组织蛋白酶B1、B3和L显然在大鼠肝脏细胞内蛋白质分解中起主要作用，因此组织蛋白酶D在该器官中的主要任务是降解细胞外蛋白质。
